As a lifelong cat owner my last cat lived to be 19. She was with me through a LOT and when she died it was like losing a close friend.

People think dogs are better companions than cats but I disagree. Cats are GREAT companions and provide a LOT of emotional support.

Since you are not stable enough from a psychiatric POV, then yes, a cat makes a perfect companion. I would get 2 cats if I were you. 2 cats can keep each other company.

How Cats Help Improve Mental Health | The Catnip Times

A cat's purr provides healing emotional comfort. Plus, when they sleep on top of your head, or chirp or chatter at you; your heat will melt into the floor.

If you are not able to get 2 cats, then 1 cat will suffice. I say, go for it! You won't regret it! They are awesome companions, cats!