HELP do i have a uti

Hi, about 15 minutes ago i went to the bathroom and it burned so so bad when i peed. It’s still burning even while i’m trying to sleep. Do i have a uti or a kidney infection? I’ve been having really bad back pain. I did just get off of an antibiotic though about two days ago and it was for me getting my tonsils removed. I’ve also been really nauseous and weak and shaky. HELP