Thanks for all your advice. He's still not putting that back leg on the ground.
I did a lot of massaging this morning and I laid him on my lap on his back and he just relaxed, passed out and let me massage his legs and hips. He's laying down a lot more than normal so I know he's not totally himself. Plus he never just relaxes on my lap for 10 minutes asleep!
I was under the impression that LP was more when they would limp for a few minutes, and then be fine, etc. This has been going on since yesterday around 1pm. But I'm for sure going to get him checked out for LP at the vet. I really want to get him in tomorrow so I'm going to have to work around this wedding.
I'm pretty positive it's not glass or anything because I literally see nothing.
I've been picking him up to go outside so he doesn't use any stairs and he's staying on a leash for potty breaks. The thing I'm not understand is he literally had like no activity yesterday minus the 3 on-leash potty breaks and he randomly started limping. We had done trick training earlier but I don't think a few of his tricks would have made him limp this bad.
I'm definitely going to try and get him into the vet tomorrow.