Advice please

Je

Okay it's a bit long but please bare with me. I have major migraines the ones that disable you from doing anything, nauseous all day, very light headed half the time. I can't take the Tylenol 3 anymore due to me being pregnant again. So doctor advised me to drink a coke(coca-cola) & munch on something cold. Here's where my dilemma comes in. In my last two pregnancies I've gained so much weight because of the coke due to the constant migraines (it helps sometimes and other times it works for only the moment that I'm drinking), I'm high risk so I can't do too much activities in one day, do y'all have any advice in what I can do for migraines??? Or what do y'all recommend, have gone through as to not gain so much weight again??? I'm already 255 lbs and 5'5. Never been this weight in my life and I really don't want to continue to gain weight. I'm in my first trimester. 😭