So scared of weight gain

So this will be my 3rd baby. I have a 10 year old and a 4 year old. After my 4 year old I started concentrating on my health and working out and dropped 50 pounds and was so good at maintaining it too. Well when my ex husband and I separated I stopped going to the gym and ended up meeting my now boyfriend and gained back about 30 pounds, of happy weight I guess you’d call it lol. I was already so upset about that weight gain and now being pregnant I am of course going to gain more. I’m excited and nervous for baby but hate that I’m so stressed about gaining weight. I hated myself when I was bigger, it just made me really depressed and I’ve come a long way so it just has me nervous.