One way to prevent loneliness is to make friends and friendship often leads to a relationship. I'd suggest being active with your current friends or in the community in order to meet new people, you never know who is just around the corner. And be patient--even if you meet that "special" person it could be several years before you're both ready to settle down. If having a child is something that's urgent to you just be sure you start working on a relationship with someone who also wants to settle down and have children--don't waste your time if you know someone isn't interested in becoming serious just because you feel lonely.
Loneliness and wanting things like children can be hard, but I'm sure there are numerous people who want companionship the same way and just as much as you who are having trouble meeting someone.
Good luck