I'm 32 weeks and going through the same thing. Its probably because baby is squishing your stomach. I try to eat but when I start eating I get full really quick.
I went through a fase of eatting non stop for a couple weeks and then this started happening to be but I am only 19 weeks and 5 days. Wasn't sure if this was normal or not also.
Ive been the same throughout this pregnancy but particularly since about 27wks, now 35wks. I just don't feel that hungry and I only eat because I think I should. My dr just says to go for quality over quantity when I do eat and not to worry too much as my baby is still huge and healthy.