I think i might have a urinary tract infection, but i don't always feel the symptoms. there's time when i feel fine, and other times i have them.

You need symptoms.: A UTI is a clinical diagnosis . Otherwise, it's not an infection. A person can have asymptomatic bacteruria or else a pyuria ( white blood cells in the urine), otherwise, it's nit a infection. This is an important distinction since you do not need any antibiotics for asymptomatic bacteriura or pyuria. Excessive antibiotic use will eventually lead to antibiotic resistance.