<human>: Recently I've turned eighteen and will soon be leaving to attend college. I'm experiencing a ton of anxiety when it comes to finally leaving high school, mainly due to separation from my friend. He's a junior, so he's going be staying behind. Most of the companions I've made throughout my senior year are juniors, I've never gotten close to someone the same age or grade. Anyways, I've developed a friends with benefits relationship with him for some time now. Besides the sex involved, I rely on him 99% of the time for support when I go through rough times/encounter situations. This is probably an indication that I should make the effort to expand my horizons and meet new friends. 

But it's tremendously difficult for me to form friendships. **Especially students my age.** It might sound peculiar but I've always had trouble forming relationships with older folk or people who are about the same age. I don't know exactly why. Just always ended up having the healthiest/happiest friendships with those who are a bit younger. 

Back to the primary problem, I really am dreading leaving my closest friend behind. It makes me feel nauseous and queasy. I really do treasure him and I'm afraid when I leave our friendship will eventually deteriorate due to lack of hanging out, etc. Even though I won't be relatively faraway from where he lives, I think the schoolwork is going become a huge burden to overcome and make time for socializing impossible. I always have the constant fear that I will end up having no friends in college because I rarely interact with people. Very prone to loneliness/isolation. I am worried about how I will manage all of this. Please help me with any suggestions. Thank you.

Give me the gist of the text in a nutshell
<bot>: What can I do to overcome separation anxiety dealing with closest friend (who's going to remain in high school for another year) because I'll be heading out for college soon? Need some advice.