UTI's further symptoms ?

I have a UTI... it came this past saturday and i was pretty sure that it was as i suspected, because of the frequent urinations, little pee when urinating, and burning when urination was finished. i did not go to the doctor though to get it checked out until tuesday, due to the fact that:

>1. it was late at night on saturday when the symptoms started and my gynecologist's office would not be open at such an hour

>2. the next day was sunday... no offices open...

>3. monday was labor day... again, no offices open...

i got a prescription for it on tuesday, just haven't been able to pick it up because insufficient amounts of money right now.

all day today though, i've had a real bad headache and off-and-on stomach aches like i'm going to be sick..

could that possibly be because i didn't go to the doctor right away and also haven't taken the medicine yet??

also, the nurse that took my UA said she was going to get a culture on the urine... two questions about that....

>1. what's that mean? the culture part, anyways... like, what is it and what goes on with it?

>2. what could she be testing it for and what could the culture test possibly bring up?