My female flat coated retriever is pacing whining and wanting to urinate frequently but can't go. I've tried yogurt with vinegar but she refuses. Could it be a UTI?

Could it, sure. It could be a stone. It could be serious. It IS serious if she can't go and urine is backing up to her kidneys. It isn't fair to keep her in pain either. Time for an ER vet visit!

Can something like this come on very quickly? She was her normal self before I went to work... came home and she was like this.

YES! I realize it's Sunday... but it's only money and you can make arrangements about paying.

Not where I live. The vet er here requires payment and its not inexpensive by any means. My dog is urinating but she tries to go more and can't.

Yes, I know it's going to be expensive, but what I meant was a down payment and a payment plan, which I don't know of any vet who doesn't allow. Or put it on a credit card?

If you can wait until tomorrow (cheaper?) because she's peeing, be sure you are with her every moment and be prepared to take her out even at any hour of the night.

I don't see a way to do a home remedy. A UTI needs antibiotics.

It could be a uti, it could be kidney problems, it could be a lot of things. We really can't even guess online.

I really would recommend taking her to the vet. This sort of thing usually comes on quickly, and if not taken care of quickly, can lead to a bad end just as quickly as it started.

Call the emergency vet, tell them the situation, ask if they have a payment plan. I don't know of any vets that will refuse to see a sick dog just because the owner doesn't have the money on hand. Most vets will work with you, after all, they became vets because of their love of animals.