Am I Exercising in My Sleep?

For the past 2 days or so my stomach has felt like I've done about a thousand sit-ups or so. Now, I'm not an exerciser, so either I'm doing it in my sleep or the little munchkin is stretching out my muscles. So far pregnancy isn't exactly what I expected it to be. I'm not complaining, I'm just surprised at how much my body has changed and how I feel. I was sitting on the living room floor the other night reading the newspaper and when it was time to get up I really had to figure out how I was going to go about standing up. My stomach does not bend as well as it used to!!
I have also noticed that my center of gravity is WAY off! I have been losing my balance a lot lately. Luckily I haven't actually fallen down, but I do start wobbling and have to take a few steps to catch myself. And I don't know if this has anything to do with my center of gravity, but I have been walking into walls like crazy!! I know that they're there, but I just can't avoid them!! At least for now I have pregnancy to blame for my clutziness!!