My bunny, Lilly, is 12 years old. She has severe arthritis that makes it hard for her to move her back legs, and we just found out she has kidney stones. The vet said she’s in a lot of pain.

She’s been on arthritis meds for about a month, and we started additional pain medication last Thursday. The vet told me that if I don’t see improvement by this Thursday, I should consider putting her to sleep.

The hardest part is that it’s so difficult to tell how much pain she’s really in. I’m 26 now and I’ve had her since I was 14—she’s been with me for nearly half my life and is one of the most important parts of it.

Her partner passed away suddenly at almost 10 years old with no signs of illness, so I never had to make a decision like this before. Now I’m faced with whether to continue managing her pain and keeping her comfortable for as long as possible, or if it’s kinder to let her go. Just writing that out is heartbreaking.

I really don’t want to lose her, but I also don’t want to be selfish if she’s suffering. Any advice or perspective from those who’ve been through something similar would mean so much right now.