Is it normal that i feel so inadequate?

Hi. I decided to write here because I whine too much to my boyfriend about it, and I don't want him to pity me (I'm sure he does).
I've always been a shy person, or at least that's what everyone always told me: since kindergarten, I remember teachers forcing me to talk to other children, repeating me not to be so quiet, that I needed friends. I didn't understand why and the fact that they were so obsessed with it annoyed me and made me isolate more. I never got along with others, not because of them of course - I've rarely met bad people in my life - but simply because it's very hard for me to comprehend them and how friendships work. I have troubles talking to people my age properly (I'm now a 18-year old girl) or without feeling "weird". I don't really know how to explain it, it's just the constant feeling of not belonging and doing everything wrong. I feel I lack in basic human skills, and I get angry with myself for that. I do cry sometimes because of it. I don't even feel alone, it's just that I'd love to feel what others feel.
I have two people with whom I talk; I suppose one would call the first one my "best friend", even though I don't have special feelings for her and we're completely different, and another one, with whom I haven't talked for two weeks because I didn't feel the need to.
My boyfriend is the only friend I have. I remember having troubles with him too at the beginning, but after a while I started to truly fall in love with him. If he wasn't there I don't know where I'd been by now. He has lots of friends and has helped me so much understanding things. I envy him. I feel like a freak because all I'm able to do is closing in my shell by getting obsessed with subjects (I love astronomy) and well, having the low self-esteem I have.
I know that there are lots of people out there with my same problem, I just wanted to say it out loud and see how common and "normal" it is. Sorry if I wrote too much.