the more you doubt it the further away results will be. maybe you should try this instead of using the anapana spot.
This is Method Two By Ajaan Lee:
There are seven basic steps:
1. Start out with three or seven long in-and-out breaths, thinking bud- with the in-breath, and dho with the out. Keep the meditation syllable as long as the breath.
2. Be clearly aware of each in-and-out breath.
3. Observe the breath as it goes in and out, noticing whether it's comfortable or uncomfortable, broad or narrow, obstructed or free-flowing, fast or slow, short or long, warm or cool. If the breath doesn't feel comfortable, adjust it until it does. For instance, if breathing in long and out long is uncomfortable, try breathing in short and out short.
As soon as you find that your breathing feels comfortable, let this comfortable breath sensation spread to the different parts of the body. To begin with, inhale the breath sensation at the base of the skull and let it flow all the way down the spine. Then, if you are male, let it spread down your right leg to the sole of your foot, to the ends of your toes, and out into the air. Inhale the breath sensation at the base of the skull again and let it spread down your spine, down your left leg to the ends of your toes, and out into the air. (If you are female, begin with the left side first, because the male and female nervous systems are different.)
Then let the breath from the base of the skull spread down over both shoulders, past your elbows and wrists, to the tips of your fingers, and out into the air.
Let the breath at the base of the throat spread down the central nerve at the front of the body, past the lungs and liver, all the way down to the bladder and colon.
Inhale the breath right at the middle of the chest and let it go all the way down to your intestines.
Let all these breath sensations spread so that they connect and flow together, and you'll feel a greatly improved sense of well-being.
4. Learn four ways of adjusting the breath:
a. in long and out long,
b. in long and out short,
c. in short and out long,
d. in short and out short.
Breathe whichever way is most comfortable for you. Or, better yet, learn to breathe comfortably all four ways, because your physical condition and your breath are always changing.
5. Become acquainted with the bases or focal points for the mind — the resting spots of the breath — and center your awareness on whichever one seems most comfortable. A few of these bases are:
a. the tip of the nose,
b. the middle of the head,
c. the palate,
d. the base of the throat,
e. the breastbone (the tip of the sternum),
f. the navel (or a point just above it).
If you suffer from frequent headaches or nervous problems, don't focus on any spot above the base of the throat. And don't try to force the breath or put yourself into a trance. Breathe freely and naturally. Let the mind be at ease with the breath — but not to the point where it slips away.
6. Spread your awareness — your sense of conscious feeling — throughout the entire body.
7. Unite the breath sensations throughout the body, letting them flow together comfortably, keeping your awareness as broad as possible. Once you're fully aware of the aspects of the breath you already know in your body, you'll come to know all sorts of other aspects as well. The breath, by its nature, has many facets: breath sensations flowing in the nerves, those flowing around and about the nerves, those spreading from the nerves to every pore. Beneficial breath sensations and harmful ones are mixed together by their very nature.
To summarize: (a) for the sake of improving the energy already existing in every part of your body, so that you can contend with such things as disease and pain; and (b) for the sake of clarifying the knowledge already within you, so that it can become a basis for the skills leading to release and purity of heart — you should always bear these seven steps in mind, because they are absolutely basic to every aspect of breath meditation.
Also Here is an alternate Translation of anapanasati (only 1st Te-trad or first 4 steps or Kaya-nupasana-sati ie Mindfulness of the body as a frame of reference/foundation of mindfulness, anyway):
Mindfulness of In-&-Out Breathing (Thanissaro Bhikkhu Trans.)
"Now how is mindfulness of in-&-out breathing developed & pursued so as to be of great fruit, of great benefit?
"There is the case where a monk, having gone to the wilderness, to the shade of a tree, or to an empty building, sits down folding his legs crosswise, holding his body erect, and setting mindfulness to the fore.(1*) Always mindful, he breathes in; mindful he breathes out.
"[1] Breathing in long, he discerns, 'I am breathing in long'; or breathing out long, he discerns, 'I am breathing out long.'
[2] Or breathing in short, he discerns, 'I am breathing in short'; or breathing out short, he discerns, 'I am breathing out short.'
[3] He trains himself, 'I will breathe in sensitive to the entire body.(2*)' He trains himself, 'I will breathe out sensitive to the entire body.'
[4] He trains himself, 'I will breathe in calming bodily fabrication (3*).' He trains himself, 'I will breathe out calming bodily fabrication.'
(1*)To the fore (parimukham): The Abhidhamma takes an etymological approach to this term, defining it as around (pari-) the mouth (mukham). In the Vinaya, however, it is used in a context (Cv.V.27.4) where it undoubtedly means the front of the chest. There is also the possibility that the term could be used idiomatically as "to the front," which is how I have translated it here.
(2*)The commentaries insist that "body" here means the breath, but this is unlikely in this context, for the next step — without further explanation — refers to the breath as "bodily fabrication." If the Buddha were using two different terms to refer to the breath in such close proximity, he would have been careful to signal that he was redefining his terms (as he does below, when explaining that the first four steps in breath meditation correspond to the practice of focusing on the body in and of itself as a frame of reference). The step of breathing in and out sensitive to the entire body relates to the many similes in the suttas depicting jhana as a state of whole-body awareness (see MN 119).
(3*)"In-&-out breaths are bodily; these are things tied up with the body. That's why in-&-out breaths are bodily fabrications." — MN 44.
also what are your intentions/ motivations/ expectations. It is possible to be too persistent. the Buddha gives a couple well known similes for this. One is not having a lute string "neither too tight or to loose" basically he's referring to the two extremes of self mortification (excessive persistence is like self mortification light) and overindulgence in sense pleasure.
I hope something here helps, and, that you get the results from the practice that your heart desires, and beyond.
Metta