Out of nowhere at around 2am last night, my cat started having shallow breaths and didn't move from his spot on my bed. He's been there all night, when usually he is up and roaming around. I tried petting him, and he didn't start purring, which he normally does, and when I tried picking him up, he started moaning. I don't know what to do because I know nothing at all about animal sickness, and it came on so suddenly. I've never seen him act like this, and I've been pretty upset all night.