I made that mistake, too, only it was not so much "lifting" as exercising. I went into the donation as a lean and fit runner. I could hardly wait to get back into shape. (You're never too old or mature to consider yourself invincible.)
After about three weeks when my stomach muscles started to feel less battered, I started my daily stretching and toning, but overdid it on day one! You're too hard on yourself because no one could be dumber than I was: I was doing crunches. (Crunches! What a doofus!) Mind you, they were little crunches, but still... I'm now sporting a small bulge at one of the incision sites. (I donated laproscopically.) It's not a danger, but people notice it when I wear my bikini.
(Just kidding. I'd have to be heavily sedated to agree to a bikini... and so would anyone unfortunate enough to get a look at me in one. hahaha!)
christine