HELP. Female at has not urinated in almost 24 hours

My foster cat (Hazel) has not appeared to use the litterbox in almost 24 hours. All she produced yesterday was a very odd shaped poo (very round and somewhat big). She is currently *mostly* secluded in her safe room, with time to roam the house during the day while my resident cat is sleeping. We have looked around her room to see if she eliminated elsewhere but it is difficult to tell. Definitely nothing obvious.

When we let the fosters out during the day I always block off my resident cats litterbox so they cannot get to it. But yesterday my boyfriend was the only one home, let her out during the evening rather than day, and did not block it off and does not watch her/them as intently as I do when they are out. So I think I was hoping she either peed somewhere in her room or went in my resident cat's box.

But I just came home and immediately checked the litter and she still has not gone. I keep trying to google this issue and search it on TCS but everything that pops up is mostly related to inappropriate, out of litterbox elimination, not no elimination. And the couple of things I found pertained to males.

A repair guy just got here so I am trying to wait until he leaves, but I assume I should take her in at this point? She is acting 100% normal otherwise, her litterbox is clean. She is on a diet of mostly Fancy Feast Classics with some Friskies Pate now and then and at night she receives a tiny amount of some really crappy grocery kibble she was previously fed by her caretaker in a puzzle treat ball. She appears to be eating normally for her (picky, picky, picky!).

Not sure how I will afford the vet at this moment (just had an enormous bill with our kidney cat yesterday) but certainly don't want to end up with an ER bill later tonight, and a dead/in pain kitty is not worth avoiding any bill regardless (we are self-fostering, so all bills are on us). But is there anything else we can consider here or try? Or any insight into what this could be? And if she happens to go before the repair guy leaves, should we still take her just in case or watch and see what happens over the next day or so?

Thank you everyone!
Monica

No need to take her in yet! Lots of cats hold on eating or going to the litter box when in a new home. If she seems normal otherwise I wouldn't worry.

She is not "new" per se, she has been with us since last Christmas Eve, so about 3 months almost. Should have mentioned that.

No change in litter box, location, or litter, either.

Ah, then if this is out of character for her I would be more concerned. Have you called your vet for a recommendation before you bring her in?

No, not yet. I am going to here in a minute. We are actually in between vets at the moment. My initial vet is closest to me, open late, takes walk ins, has emergency services, ect.. But he nearly killed my kidney cat. There are other vets at the clinic, but I am unfamiliar with them.

We got a second opinion from another vet after that one, but I was not comfortable with his assessment of Jack (kidney cat) either, so he is being treated by an internist about 45 minutes away and we are still without a primary vet.

So I am debating where to take Hazel. I called the second vet but no one answered and I think this is their surgery day. Going to keep trying a bit longer before resorting to taking her to our original vet, which I am not keen on.

I know cats mask their pain, but Hazel is acting so completely normal! Playing, active, curious, affectionate. I suppose I will just have to see what the vet thinks.