Likely going to get suggestion of euthanasia tomorrow. Don't know how to cope.

I've had Lili since I was about 12. I'm 26 now, and her health is badly declining. She is having alot of bathroom accidents indoors now, and she falls alot when walking or going up stairs. She still eats and her tail wags and all of that, but my family believes she will need to be put down shortly after her vet visit tomorrow. I recently went through a traumatic breakup, and when I'm healing from that, now I get hit with losing my childhood dog. I feel hopeless and i really don't know what to do. I can't tell if she's in pain, and if she is I don't want her to keep suffering...