Should I take my guinea pig to the vet?

My guinea pig has been acting weird today, and yesterday. Like 10 minutes ago he ran really fast to go to the other side of his cage then just stopped randomly, another time like 20 or 30 minutes ago he rammed his head into his hay. He's not drinking as much, and he doesn't want to go to the other side of his cage. Plus, he keeps falling over. He's 4 years if that helps. My guinea pigs head is only going to the right side, his eyes also keep going back and then back in the middle. I'm scared! Should i take him to the vet immediately? So, its now a little later. I've given him some water, he drank a little bit. I also put some cool water on a towel and rubbed him down, just incase he was hot. His head is still doing that thing, but its better than when it first started happening.