My cat had a urinary blockage. He went to the clinic yesterday they kept him over night and inserted a catheter; the vet said that he thinks he should be ok now but it is the next day we have him back and he was in the litter box for 20 minutes trying to pee. However he could not only when I pushed on his bladder a very little amount came out. Should he be having these issues due to the catheter? Or does he have another bloackage..very concerned and the vet was not that helpful.