Cat is acting drunk?

I came home last night after spending the day with some family who lived a couple hours away. Upon return, I realized that my cat is acting all sorts of out of it. The best way to describe it, is that he seems drunk. He can't walk straight, keeps stumbling, and seems to be staring off into space at moments. Last night was worse, he was going limp and his body seemed to be stiff. Today he's acting slightly better. He's eaten, drank water, went to the bathroom, hopped up into his favorite bay window and is currently purring. I'm still not sure what caused it, though, and it's still extremely worrying. I don't have a car today to take him to the vet until later.

I would get him to the vet as soon as you can. Take a taxi or uber if you need to. Something neurological might be happening, and time may be very important for something like this.

my first thought is your cat may have had a stroke.  there are lots of other things that could be the problem, but do get your cat to the vet SOON. 

Is your kitty strictly indoor?  Is there is any way that he  could've gotten into antifreeze?

He's strickly indoors, so there's no possible way for him to get into antifreeze. I found out that my parents left some.. Herbs out, irresponsibly. I think that he may have gotten in to. He's better now, but I'm going to keep the vet appointment anyways.

Best keeping to a vet appointment with something like this.  If you have an idea what he might have gotten in to let the vet know too as it will help them know what to check out, like if there is any risk to liver or something.  Cats can sometimes be like you describe if they have epileptic seizures too.

A friend of mine inocently gave me a lovely bunch of gladioli flowers when Mouse was about 9 months old.  They'd only been in the apartment for about 5 minutes and he started chewing on the flowers and leaves.  Nothing I'd seen before said anything about gladioli being poisonous to cats so I didn't think too much about it until maybe 10 minutes later when he was sitting on the floor in front of us but at a definite angle and his eyes seemingly unattached to his brain.        He was most definitely having 'an experience' I would have preferred him not to.....   You can imagine my relief when he returned to normal 10 or 15 minutes later - he was kind of sleepy but fine after that.  Yes, gladioli are listed in a thread here on TCS as toxic to cats.   The cat at an angle was enough to panic me, staggering and stumbling and staring off in to space definitely warants a good check up. 

Yes, definitely take him to the vet still. Also tell the vet about the "herbs" even if they weren't legal ones to make sure he gets the right treatment. Marijuana can be very toxic to cats, and vets do not have to report that sort of thing.