UTI help!!

So a few weeks ago I had stinging when I peed and a lil bit of blood and I was like ok this is probably a UTI so I contacted my doctor and did a urine test and she said it’s clear but she gave me antibiotics anyway. I’m thinking I had an infection and it went away on it’s own because I’m never ill and I have a pretty good immune system but she wants to do further tests because she reckons the blood when I peed (which has gone now) wouldn’t go away on its own but I don’t think it’s necessary because I think it was the infection and it went away on it’s own. Would it be the infection or could she be right and something else is going on..?

Btw I no longer have any symptoms at all and I feel completely fine