Sounds like the infamous Induction Flu, jaybee

... but one of the veteran Atkineers could advise you better than I. Other than some serious sugar withdrawal and feeling a bit of "the vapors," I didn't have any major side effects during the transition period. Hang in there!
Did my circuit training today but may be switching gyms, as climbing off and on the equipment seems to be what triggers the bruising on the back of my legs ... think a workout on a treadmill and rowing machine would suit my purposes just as well, sans the ugly black 'n blue marks!
Hope you feel better, jaybee ... have a good day, everyone!