Yeast infection advice??

For whatever reason, I am super susceptible to UTIs, which seriously sucks. I got at least 3 my freshman year of high school, while I was still a virgin. I’ve had sonograms of kidneys and my bladder just to ensure there was no underlying condition. I don’t have one, but I still am prone to these god awful infections. I think I had another either sophomore or junior year but they started to die down. I’ve never gotten one from having sex until recently. I had sex with my boyfriend with absolutely no form of contraception (I know I’m not very smart). I’m not so much worried about being pregnant because I know where his cum goes when he have sex and it’s not my vagina 😂 but lately I’ve been having these symptoms that seemed to resemble a UTI at first but now it seems like it’s a yeast infection and I have never had one before. I got Monistat and it seemed to be working but it feels like it isn’t now. My stomach has been cramping like crazy and my periods due. I’m not really looking for answers because I don’t think there’s anything I can do but I just really needed to vent 😂😂 however if you have any advice on yeast infections please share with me because I just want to be able to have sex without worrying about this bullshit