Sometimes I feel the same way, I have no friends or anyone to help me keep my mind from thinking of my bf while he's out for day having fun with his friends! The only thing that has truly helped me is getting lost in a good book. Go to park and enjoy the fresh air and a nice book. Or go for a drive in the mountains or the beach. Hope this helps.

Thanks

Have you ever tried meetup.com to find activities to do with groups of people without having to really get close to them. You just sign up for the activity you want to do and show up. That way you can get out and about, and find things to do without having to really connect with the people unless you wan to.
I have found it a very useful tool, and slowly over the couple of years I have been in some groups I have made some friends. It has really helped with the loneliness at times.

Yes, I am a member a go a couple times a month and that helps.

Yep, I'm in the same boat as you. Seeing as all my close friends are in serious relationships it just makes it even more frustrating. It's difficult because I probably seem very "reserved" at first, and that turns people off.

Whenever I try to talk to someone close about this, they say "Oh, you're just 18 you have time!"
Unfortunately I can't change who I am :/

As for advice, I'd say get involved in something such as volunteer work, etc.) you'll meet high quality people.