fridtjof amundsen:
Is this an issue that will last very long or is it common to get over it? I am reading about people living with this for years. I think that is what makes me very sad.

It can last for very long, definitely. Particularly if one does not get good advice and directions on what it is and how to deal with it. What surprises me a bit about your description of your practice is that you have spent substantial amounts of time practicing, based just on a single video (I am curious which by the way!). Given the descriptions that you give of your progress, it is possible that you have some talent for concentration, but I think that, at this point in your practice, you would benefit from reading a bit about meditation technique, stages, and so on. Moreover:
Progress:
What I mean about progress is that the spaces between thoughts were longer during meditation. My concentration was getting better. I got more clearity and presence in the moment while doing things in my everyday life. I did things to improve my life instead of distracting myself with tv, facebook and junkfood. Blindspots on how I was as a person and how I could improve appeared etc. I was feeling more at peace with the world and got a sense of true self esteem. No more anexiety. My life automatically got better.
Effects decreasing and lower self:
The effects that was decreasing was the same as what I listed above. Basically today I have trouble doing schoolwork. Have trouble smiling in social situations. I feel depressed and have a pretty negative outlook on how this will end. What I mean with the lower self if the opposite of the higher self. My lower self likes to argue, blame, do egotistical and greedy actions. I only care about myself, which is not a position I like to be in.
Yes, it sound like the Dark Night, or something very similar to it. These mood swings are known (I had written "well" known, but I had to correct myself: unfortunately, they are not as well known as they should be). The best source available to understand and deal with them is
Mastering the Core Teachings of the Buddha. It is almost 400 pages long and I understand that it can be daunting, but I do strongly suggest that you read it. You will also get a lot of tips on how to practice, what is vipassana, what is samatha, and so on.
If what you got yourself into is indeed the Dark Night, by all means, read it. It can save you.
If you want some pointers on how to meditate in an alternative way, that might possibly, temporarily relieve both the feelings of pressure in your head and bad mood swings, give this a shot:
http://www.leighb.com/jhana3.htm
this is the equivalent of two pages and you might try it immediately - do not expect immediate results, but who knows, it might help with the head pressure thing and with your mood too.
If you want something brief to read about Mahasi-style vipassana and what the Dark Night is, try this (about 15 pages)
http://www.saraniya.com/books/mahasi-sayadaw/pdf/mahasi_sayadaw-1944_practical_insight_meditation.pdf
and this (about 35 pages)
http://www.saraniya.com/books/mahasi-sayadaw/pdf/mahasi_sayadaw-1944_progress_of_insight.pdf
But these are just shortcuts. Do read MCTB above.
Whatever you do, keep us posted.