Little_tippler, I can honestly say that I completely understand what you're going through because I've gone through all of that myself. I'm almost turning 24 and I've had a low libido (even though I find my b/f very sexy) and was scared to "venture" and explore sex.
I never enjoyed oral sex (giving or receiving) until just recently because I felt self-conscious about it. What I've discovered is that you honestly just have to let yourself ENJOY what sex has to offer and allow yourself to feel good without feeling guilty. You can also feel good knowing that you're making the person you care about feel REALLY good, too. I was brought up to believe that sex was sort of a "no no" thing and plus, my own self image didn't help me be adventurous in bed, either. When I did have sex, I was always self-conscious of whether I was good or not and how I looked naked, etc. and never allowed my "full potential" to come out.
If this is similar to what you're going through, then know you're not alone. I'm still working on it, too, but if others get to have so much fun with sex, so should we!!
Just allow yourself to enjoy how good sex feels and know that youre SO thinks you're VERY sexy and desirable.