No appetite

I’m 17+2 and have absolutely no appetite. It doesn’t seem like I can ever finish a meal and it’s starting to worry me. I’ve gained a little bit of weight but only around 5 lbs. Before I got pregnant I was 140, now I’m 145. With my girls I ate so much and gained a lot throughout my pregnancies. With this one (we won’t know the gender until 20 weeks) I just can’t ever seem to eat anything without being full right away. Has anyone else dealt with this? I’m just hoping the baby comes out healthy and I want to be able to eat enough but I’m just full all the time. 😢