making friends

Okay lately I've been feeling kinda lonely. I do online school, but work 50 hours a week. All of my friends from high school are at college. And when they come back we hang out, but obviously that's not very often. Plus I'm only close with two of them still. The others I only hang out with if it's the whole group. In high school I had so many friends and always had someone to do stuff with. But now I just always feel alone. How do you make friends as a young adult?  (I'm a nanny, so I can't make friends at work and love my job so I wouldn't leave it)