Workout during pregnancy

So I just found out this last week I'm pregnant Yay baby #4 but anywho, I was planning on starting to workout before I found out but I have a flabby tummy. We had a miscarriage in Jan/ feb time frame. My question is this what can I do to help the flab ( I don't  wanna show "early" due to being fat ) But I don't wanna do anything to lose this baby. I know walking and stuff is good workout but I really wanna help lose the extra flab before Baby starts to show 😏😉 ideas?