Sex drive

Hey so I think I have a very low sex drive and I’m only 17. I think this is bad and I need help figuring this out because I have a boyfriend who I really like and every time he asks if I wanna have sex I say no because I’m never feeling it!! I only feel like it when I’m on my period and it’s no fun. We did talk about how I never wanna have sex but I didn’t know what to tell him because I honestly have no clue either and it really bothers me not knowing why my mind and body doesn’t want to be with him. Like he’s hot and everything I want in a guy but I just don’t feel like it. But I think one of the reasons is that I’ve never finished before so maybe that’s why I don’t feel like it i don’t know. I’ve been sexually active since I was fifteen and probably have had sex over 15 times and never have finished and had six partners and still have never. I really don’t know what is wrong with me but it’s getting worse to the point where I don’t even wanna have sex with my BOYFRIEND like wth. Like it only feels good when someone is fingering me and that’s about it. Intercourse? Nothing. Getting eaten out? Nothing. I hate faking it every time and I hate not wanting to have sex. Can someone help me out!! Give me some advice, should I go see a doctor?