Cat licking vulva and not peeing

7 year old Female cat with no health problems started having trouble to pee and poop for the last 2 days. Took her to vet and did blood test. Vet said it couldn't feel the bladder so it was empty but stool was very hard. Didn't have the money to pay for urinalysis and x-ray. Results of blood test havent come back yet. Cat is eating little as usual and drinks water. Every time she tries to use the litter box, she comes out and licks the vulva, Havent noticed discharge because she probably is licking off.
   
I dont have much money to spend but I dont wanna lose my cat! Please help! Thank you.