22 weeks along, hunger has dramatically subsided?

I'm 22 weeks 2 days now and my hunger has dramatically subsided. In the first trimester I didn't think there was an end to my eating because I was so hungry. But as I got into my second trimester, I've been noticeably less hungry. I'm pretty sure I eat the same and often times even less than I did before I got pregnant. Tonight I had some salmon and stir fried bean sprouts and 30 minutes after finishing I felt sick to my stomach from being so full. It was that feeling you get after thanksgiving or a buffet and you feel like you have enough food in your stomach to last through winter. My mom said it's because my baby is pushing against my stomach leaving less room for food, but is that true? I'm also only gaining 2 lbs a month which my nutritionist said isn't as much as he'd like but it's just that I am not that hungry. Anybody else experience this loss of hunger?