Michael:
My practice has gotten better in duration and concentration and effort.
This is the only proof you need that, whatever is happening in phenomenological terms, you're doing it right.
If you're cycling then your general baseline will be dependent on which ñana you're in, this will then influence the quality of your attention and your ability to focus on your object. Remember, you're not trying to stop thinking or prevent though from arising, just observe them and return to the breath; if you're having difficulty finding it, use a more physical anchor like the abdomen to keep track of where you're at in the breath cycle.
Don't beat yourself up, don't force anything, just keep on gently returning the attention to the object and you'll get to where you want to be. You seem to really "want" to get into jhana but it doesn't come about that way, learn to relax and enjoy your practice 'cause it makes it so much more fun.