Self-Loathing, Not Sure What to do

Hey there, Ugh so this story is a bit messy, but I'll try to tell it the best I can. So I am a relatively recently un-closeted gay black man currently living in the south. I am currently 18, and still a virgin. My family is extraordinarily religious (I'm religious to a degree, though pretty moderate) but they actually took to me coming out very well. I lost a couple of friends, but I most stuck around so that was okay. My issue stems from the fact that I've been dating a guy for about 3 and a half months now, but I've not been able to bring myself to have sex with him. He's attempted to initiate multiple times, and each time I've turned him down. It's not like I don't want to have sex with him, I find him amazingly attractive, and often fantasize about the possibility. But... Every time I get close to doing the deed there's just some psychological thing that fucks me over, and I can't do it. I just feel so... Dirty. Or rather I feel like maybe what I'm doing isn't like good or something, even though it's what i really want to do. Idk its kind of hard to describe. I have a lot of self hating thoughts due to being gay, like maybe what my pastor says is right and I'm like this terrible sinner, or what if I'm really just sick or something? I don't know. I don't want my bf to leave me, he's an amazing guy and I hate to keep letting him down, and at the same time I feel like I'm missing out on an experience with a person I deeply love and care for. Idk, is this typical? Or am I really just fucked up? Is there any way to get over it? Sorry for this hella long post, I just figure if I can't talk about it to anyone else, I may as well scream it into the void.