Why is my cat hiding in closet?

I was about 5 months pregnant when my bf and I got our cat. She is 5yrs old. She became comfortable around us, and the only problem we had was she was pooping outside her litter box for a couple months before we got that worked out and now she doesn't. But now that I am almost 9 months, she has become more and more secluded and sleeps in the closet alot. She looks depressed, and doesnt seem as playful and sociable as she was before. I am worried that she is unhappy here. But, I have not changed anything major, or ignored her any. Her routine is getting me up around 6 am or so for her portion on tuna. She wont eat anything else except that.She does eat "expensive" healty crunchies throughout the day. But as far as getting me up, its for the tuna. If she goes pee or poop in litter box, I give her a few temptation chicken treats (the only kind she goes nuts over). But after she has eatin, she goes right back to the closet, and looks so down. I try to get her to play with the cat toys like she usually did, but she seems to have lost interest in them....she really looks depressed. I feel her ears to make sure she doesnt have fever. My question is "Is it because I am so close to having the baby that she senses that and is somehow bothered by it?"