Kitty try in A Day in the Life of Me

So.. Sunday we tried to adopt a friends cat, because she has recently been diagnosed severely allergic and one of the two she has has REALLY bad skin issues to the point the top of her coat is just always sprinkled in dander, which is what my friend is having the issue with..
Sunday night she dropped her off. My boy here was just so excite, he wanted to make friends so bad, but she wasn’t having it. She just hissed and growled all night as soon as he came near, which is understandable.
Yesterday, she was still grumpy, but she was up and came in on the bed, as she spent the whole night on the couch, took me about an hour to get her to eat breakfast (wet food). Turned into brunch by the time she would. Went to work, hubby was home with the two of em, he took her into the den where the litter box is and she didn’t want nothing to do with it.
She didn’t want nothing to do with the food or water in the kitchen, just to be on the couch, and petted.
This morning, same thing, came in up on the bed when she knew we were up, my boy came up for cuddles, she hissed and growled to the point he was scared to stay, so i brought him out to the couch, curled up, grabbed his blanket.... it was damp.....
She’d peed the couch :(
I debated hard about to msg my friend or not. Finally I did, only because she has so many other health problems, and my friend was insistent she would never make a mess, and never HAD.
Back and forth for about half an hr, we decided she take her back, and take her to HER vet.
She got home, chowed down… threw up, and then ate again… lil frigger…
apparently she hadn’t been to the box though still by 1pm so she’s thinking there may be an issue we weren’t aware of :(
hopefully tomorrow we will know more, and it was just stress.
She’s had a hard life, and i was more then willing to give her more time, but her mom wasn’t lol
She really was missing her, and I would never keep her from her kitty.
But we miss her already, my poor boy has been sulking most the day since she left.