I just recently blew out my lower ab muscle and had to learn a few tough lessons. Are you doing abs daily? When we do exercise, sit ups, lifting weights, etc. we are challenging our muscle fibers. We are stretching them to grow so they break and need repair. Fortunately our bodies do that naturally, but that means that area requires some rest. That’s why you’ll hear people say things like leg day, arm day, booty work, core day etc. I alternate my days as well and rarely do the same exercise twice in the same week. I tend to need 2 days rest after an ab workout day. I know we are eager to get that old thang back, but it takes time just like we slowly gain weight, it takes time to get it off and re-sculpt.

Good Luck