Uti? Advice please ❤️

Hi ladies.

I've been having really bad pains when peeing and that's extended to being a rather constant pain. I just assumed it was a uti and that I'd get over it soon enough but it's been a week and the pain has been waking me up at night and has been quite severe in the past two days since I got my period.

I think I should probably go to a doctor but I'm 16 and I'm staying with my grandpa while my mum is overseas and I don't know what to say to him. She won't be back for a few days and I don't have money to pay to go to a doctor. What should I do?