Considered overweight pre-pregnancy and 17 weeks pregnant but no weight gain and hardly an appetite still. Anyone else going through this?

Br

Ok so i'm on my third child ( I have a 10 year old, 1 year old) and am in my second trimester. I'm currently under the weight I was at when I got pregnant and I have a hard time eating. I know they prefer for me not to gain too much weight in my pregnancy due to my pre-pregnancy weight but I still worry a bit. In my mind I feel so hungry but when I finally try to eat I can hardly eat what's on my plate. Has anyone else experienced this? Makes me a little nervous about my babies birth weight