I am the same way. The cure? Well, you need practice. Start out by smiling. Make eye contact and smile. Then when you get the wanted response and you get your nerve up, learn to small talk, starting out with Hi! How are you! It is putting yourself out there and that simply takes doing it, facing your fears. I do not make friends easily. When I do, they are lifelong. If my so called friends do me wrong, they only do it one time. I drop them. I am not mean about it but I hold friendship very dear.
You said within your circle you are very lively so it sounds like to me, you just need to learn to be a little more outgoing and the rest will take care of itself. But when you first start doing it, it is soooo scary and feels weird I know. But the more you do it, the more you are comfortable with it. I know people who drink just to come out of their shell in social situations! Its kind of like a phobia to them.
I knw that feeling... I am the exact same, I am shy at first when I am around people, but the life of the oarty with my friends... lol.... The fact that I was in a terrible relationship for 2.5 years made it a lot worse!!! So I know how you are feeling!!!! I feel like everyone is out to get me, that they don't like me and all that stuff.... But what I have learned through counselling is not to care about what other people think, in reality how does what they think about you really affect your life???? It doesn't.... Its all in your head!!! Im still putting that into practice!! Its hard!!!
Im from Ireland, and right now Im in Alaska for the summer.... Before counselling I never thought Id have the courage to travel so far from home!! Id recommend trying some things to boost your confidence and self-esteem!!! But unfortunately I don't have any tips cause I am still trying to be more confident!!! I guess all you need to do is love yourself completely!!!
Good Luck!!!!
Jen x