Pregnant and paranoid

I can't seem to stop raking my SO over the coals about where he goes and what he does in his free time, I feel so sure he's keeping something from me. What's worse is I feel like I'm picking fights but his stories don't seem to add up. Is pregnancy making me paranoid? I feel like I'm destroying us, and the first few times he seemed forgiving of my suspiciousness, but now he just gets defensive. Is anyone else experiencing more paranoia that usual?