Cats, Bowel Infection I Have A 7 Year Old Cat With Blood In Bowel?

I have a 7 year old cat with blood in bowel? - cats, bowel infection

I went to the vet and first said I had an infection, so it was an antibiotic for a week and do not change, then drove me back and told me that I'd have to set for drugs and said it should be better within a week . Who was 2 weeks and see the change. Does anyone have any suggestions?