gaining plateau

I am trying to gain weight (not bulk just gain) back story is basically some growth concerns were brought up along with the fact that id yet to really gain anything at 32 weeks preg I was told to fatten up to get plenty of nutrients to baby and get growth back on track.

I started on 3500 callories a day and did pretty great actually i gained 6 lbs in 2 weeks but I was haveing a hard time reaching that intake amount and stress was starting to be detrimental so i knocked it back to just 3000 cals a day to give myself a little mental break. the next 2 weeks I only gained 2 lbs. I decided just to stay at 3000 cals though becuse I figured It was just my body leveling out after getting used to the higher intakes. its been another week now and somehow Iv lost 2 lbs i have no clue how I dont allways make it to 3000 sometimes I forget dinner to be honest its hard for me to eat at night idk why so intead i nomally have 2 or 3 breakfests. & today i actually ended up at 3600 beceuse well me and the PB&J had a little to much alone time lol.

anyway I really need to keep gaining for the next 4-6 weeks and im not sure whats going wrong.. Ill be honest I havnt been very balenced on fruits and veggies but iv been eatting tons of meats chesses eggs nut butters breads and such which should be better for gaining anyway I drink breakfestt shakes and take prenatles so i shouldnt be vitamin deficient. Im at a total loss If im going to have to keep upping my intake i honestly dont think i can its not even mental i just cant stomach that much i get quessy and feel sick just looking at food after more then 3 days at 3500 or more. theres got to be a better way to get possitve results.