The weight won’t stick,help!!


I’m struggling to gain and keep the weight I need help! I’m 30+1 pregnant this is my first pregnancy, yesterday my doctor told me I need to eat more but all I do is eat. And when I’m at work all I do walk around so I basically burn all the fat right off. My doctor says my baby is healthy but he would prefer/ want him to be bigger, and right now he weights at 3 lb 2 oz and lady who did my ultrasound told me that’s good but my doctor wants me to gain more weight for the both of us. I’ve been weighting at 150 since January and I can’t figure out how to keep the weight.

Also I eat like five times a day, and just a lot of meat and starch