Weight gain struggle

In the past 3.5 weeks I've lost half a pound. I'm almost 27 weeks and have gained about 14lbs, which is somewhat normal (I usually gain btw 25-30lbs each pregnancy) but I'm worried about the fact that I have stopped gaining. I'm just not hungry! Nothing sounds good except things I don't have or can't have (please just let me have some raw oysters!!!) and I can't seem to bring myself to eat a lot of stuff I don't really want. Any suggestions on ways to add some calories to the little food I eat?