Lydia,you feel lonely in the midst of people because
1)you dont take interest in what is going on
2)you dont confide in anyone
3)you dont trust people enough to lower your guard
4)try to be the friend to others which you want them to b for you

by all this i dont want to be judgmental but i want you to consider why things are this way so that you can mend matters
All the best to you