How much are vet bills in the UK?

I baught a fancy pet rat from the pet shop two weeks ago and i think she is pregnant.. They said theres no chance she could be pregnant however she is showing all the signs of pregnancy. She has made a massive nest and baracaded herself in, stashed food in her nest, she turned aggresive towards me about a week ago and keeps biting altho before she was fine, she keeps stretching, moving around and making a new noise, like a muffled squeek but not high pitched, she also has two spots of blood on her bedding.. Ive never had a rat before and had no idea she was pregnant when i baught her (thats if she is) do u think it sounds like shes pregnant? Also her vaginal opening is open and usually they are closed and her hips look more broader.. I dont no weather i should take her to the vets or not because i dont want to stress her out or cause complications for her pregnancy, also vet bills are really expensive and i dont have much money. How much roughly would it be to take my rat to the vets to see if she is pregnant and would i have to pay for a consoltation fee? Any advice would be much appreciated (: thanks