Sounds lot like our girl. We got from rescue, she was saved from fire in which owners died. She lived on in house until rescued. Vet guess she's about 10. When we got her she'd just had surgery including teeth removed and neurology problems. We've had her 4 months, chipped, vaccinated etc. She was scared and anxious when came to us, pulled out clumps of fur, pissed in bath (used litter tray for a crap). I stayed up all night with her, just stroking her as she lay on my lap. No one knows her name so rescue named her Phoenix (as rescued from fire). About month ago noticed struggling to walk, almost like drunk, staggering and back legs not supporting her. Had meds for 2 weeks then x-ray (cost £417). They suspect arthritis of spine intially. She's lot better last few weeks, cut her tablets down to one a day plus 400mls of liquid via a syringe. We didn't take out insurance as she'd loads of health issues when we got her so put £100 a month into a savings account. Can't imagine my life without her now. I'm working from home and my company all day. Hope your cat gets sorted and makes you as happy as mine does