Ab separation

My abs separated my third trimester with my first. This time they have already separated! I'm only 22 weeks. I was a mess after and couldn't lift anything. I've been exercising my whole pregnancy to try to prevent it. I quit abs second trimester to try not to pull them apart but I have the tenting in the middle of belly. I'm kinda upset because I was so weak last time. Happen to anyone else? How long were you told let them rest?