ab exercises and "bloating

 My stomach muscles have always been extremely and ridiculously weak.  I've recently decided to add ab exercises to my regimine.   I'm doing my best and it's killing me.  I've only been at it a week every other day.  I do what I can.

I noticed that my stomach seems swollen or bloated today and my jean shorts feel tight around the waist.  Has this anything to do with my body adjusting to this new additional exercise?

I read somewhere that after working your muscles , water or fluid would surround the muscle to aid repair or something along those lines.  Could this be whats happening to my belly?