Wedding and pregnant help!

serinity • 👦🏼👦🏼👧🏼👧🏼👶🏻TTC I’m a mechanic and proud of it

So I'm due April 9/10th ish area. I'm getting married may 18th (3year anniversary) I have a 1 year old (may22nd) and I gained 18 pounds with her walked out only 1 pound heavier than I was before I was pregnant. I am afraid I might gain more this time around I'm thinking it's a bay and I just want the best advise on watching what I do and eat or what to do if I gain to much! I do not want to alter my dress! (Picture here)