I am going through very similar problems with balance! I am about to move, applying to PhD programs, on top of a thousand personal responsibilities and relationship obligations so basically I know how you feel.
I haven't been that successful in balancing so far but I have been trying to say "no" more often when people ask me to do things or something for them. I have also been trying to be clear about my time limits without being rude (especially with friends). It is very hard to try and lose weight and eat right when you have too many obligations.
So my advice is to work on spreading out your obligations and trying to say "no" more often so you can give yourself space to think and work.
Any advice from others is much appreciated as I am still working on this balance thing as well!