My Cat Has Become Very Disconnected. He's Extremely Skinny Like

My cat has become very disconnected. He's extremely skinny like I can see his spine and feel his ribs. I just tried to feed him and he wouldn't eat. I've not found a tick on him but he does go outside a lot so I'm worried he's been bit by something or could he possibly have worms? I can't tell on the worms because he likes to go to the bathroom outside but he is very bloated. He's just a little over 1. I'm so worried about him. Also he has made a get back kind of noise a few times at my son and they've been best friends since we got the cat little over a year ago.