Concerns for baby...

St

I am about 17 weeks now and I don't feel sick but I have no appetite now. I eat to try to eat but then it makes me full so fast that I can't finish any meal and if I do I feel so sick for some time. I get thirsty a lot but not hungry. I try to snack a little and even then I'd have to snack an even smaller amount because it's too much. I don't know if that's normal or if I should talk to my doctor and be concerned..