No sex drive :/

For about a year and a half I have had an incredibly low sex drive, like having sex only once or twice a month. This has been weighing me down so much because I feel very insecure about it and guilty that I have not been able to please my man the way he deserves it. I've been with my boyfriend for almost 2 years now and he has been so patient and so graceful but the guilt and shame has taken over me almost completely and I truly don't know what to do. Although it's been a year and a half this still shocks me because I used to fuck like a little horny rabbit for years! Ladies, please help!! What should I do? I have been sexually active since I was 15, I am now 22 and have still never had an orgasm from penetration. I am wondering if there is a direct correlation between my low sex drive and the fact that I can't come (from having sex, strictly clitoral)? Idk, I'm stressed the hell out and I need some tips, suggestions, comfort... Etc. Do I need to see a gyno about this or a sex therapist? I'm desperate and incredibly ashamed.
Thanks ladies! Xo