No orgasm . 😓

Ok, so.. I'm 19yrs soon to be 20 . I've been sexually active for 3 years now with one guy which is currently my boyfriend & we've been together for 4yrs, he's had sex with 2 other girls but this was when he was 16 17, he is now 22 but anyway he was also under the influence, he used to pop pills & what not so I would figure jus with those two he really didn't have much experience nor did they teach him anything knowing it was jus a quick hook up . So when we get intimate , he turns me on, it feels good in a way but not once have I ever had an orgasm having sex. I feel so ashamed because I have never told him this... & this is only because he's really insecure about himself, he's over weight & he's really insecure bout his private area because he feels it should be a " MAN " size . So I've never told him because I don't want him to think I'm not attracted to him nor do I want him to think that his penis isn't good enough . But I kno it can't be him because we do have a dildo & I have tried using it when he's not around to try to find my " Gspot " & he's also used it on me , but even then I jus don't feel anything , I jus don't get an orgasm... But I do get aroused & an orgasm playing with the clitoris . But I jus want to be able to experience an orgasm thru intercourse . I've never talked to anybody about this because I'm jus so embarrassed & don't want anybody think oh her man can't satisfy her or he has a small one . But also I think what the problem is, is that I think to much.. So because I think to much & can't focus it doesn't help with trying to orgasm. Also he does climax pretty quick . He usually last longer when we're drinking.. Someone please help. Idk what to do, & I feel like there's something wrong with me & becoming depressed.