Think I might have a UTI??

So as soon as I got off my period my vagina has just had this discomfort, and it just constantly feels like it's hot and on fire and stings, mainly around the clit area. When I pee it doesn't hurt too bad (when I had a UTI before it stung like a mf) but it doesn't sting too bad this time. And when I took a look at it, it is red and looks really irritated. I think what might have caused this was leaving a jumbo tampon in for too long. I didn't change it all day, even though there was barley any blood on it. And the last time I had sex was last week but it was only for like a minute, like literally.

I've never visited a gynecologist before (i'm 17) and I'm too nervous to talk to my mom about it too. That's why I'm hoping it's just a UTI so I can take some pills I already have for it.