How to not gain too much weight this pregancy?

I had my first baby at 21. I started out 105 pounds. Ended the pregnancy at 155. After having my daughter I was 135 pounds. I started off really tiny.. I was super sick a lot of my pregnancy and snacking, especially on carbs seemed to help with the nausea and puking

(Total pregnancy weight was 50 lbs)

I found out I was pregnant with my son (baby number 2) 10 months later.

Started the pregnancy at 135 ended it at 170 pounds and after I had given birth I was 150 lbs.

total weight gain with high was 35 lbs.

I wasn’t as sick so that helped.

I dieted after breast-feeding him and got down to a total of 130 pounds again.

Now we are expecting baby number 3 and I am so sick. They put me on prescription nausea medication. And I am currently 10 weeks and I’ve already gained 5 pounds from snacking frequently.

I’m nervous this baby‘s gonna be like my first go around and I’ll gain 50 pounds but this time start at 130 pounds.

I’m super stressed out, my OB already talk to me about how much weight she would like me to gain.. (30 lbs).

I’m just feeling really depressed about this and I don’t wanna make excuses up and just scared I’m gonna end up overweight.

Does anyone have any suggestions? Vegetables as snacks do help but when I’m feeling really sick it seems like carb food are what actually help me

Dry salty snacks.

Anyone have any advice or who also struggled with too much weight gain while pregnant?