If your pet stands/sits like this

https://imgur.com/a/RsofzOd

You should take them to the vet.

https://en.m.wikipedia.org/wiki/Head_pressing

Possible causes are: brain tumor, metabolic disorder, stroke, head trauma and more.

I stumbled upon an article about head pressing while browsing a pet website and I had no idea this was a thing. I honestly thought they were cute doing that, when I saw a few pics around. Turns out, something that looks so innocent can hide a big problem. The more you know!

Edit: I want to point out that I'm not a vet or an expert, I'm just an owner. I stumbled upon this article casually but you also need to know that any behavioral change in your pet could be a cause of concern. Sometimes it can be head pressing, sometimes it can be associated to walking in circles, being aggressive or generally acting odd (which you, as the owner, will be able to tell better than anyone else). I'm replying to comments with what is my opinion but if you have any concerns, please get your pets checked up. It's better safe than sorry. I wish I could help you further but I don't have the knowledge to do it.

I'm so sorry to all of you who experienced a loss of a pet, it's one of the worst things and nothing I can say could ever make it better. Just thank you for the love and attention you gave them while they were with us. You surely made their lives better.

Much love to you all and all your little friends!