I am horribly shy, what can i do to fix this?

i am so shy that if i walk into a room and see people in it i will go the other way and wait until everyone leaves. my family calls me anti social sometimes i would just rather be alone than have people judge me. just being alone with my thoughts makes me happy or getting out into the world it's like having two contradicting spirits. one of being adventuress and the other of being shy. like i love to ride roller coasters and drive fast cars and when i get around people during the times im doing these things im more out going and fun. but other times when im going shopping or just getting the mail i am bashful and meek. can anybody make since of this what the heck is going on with my emotions and/or mindset???