I think you will have to get your courage up, and get your interest up, show interest in others, get involved in group activities....in time, you will find a friend or two or three.
I too tend to feel isolated. There are times when I have had friends, and a few have been there long term, just a few and that is enough. I know that when I am feeling isolated it is because I am stuck inside myself instead of looking outward, around me at the world and others. When it gets bad, I talk to strangers at the next coffee shop table, say hello to others on the street as I walk, watch...and use my camera to wander, look, see, find, and document colors, shapes, and scenes that please my eyes.