Hi there!
I feel for you and can definitely relate. I befriended someone in my 2nd grade class and immediately hit it off. We were pretty much best friends since then. But around 6-7 grade our lives started to drift apart. We didn't see each other a lot. We would chat every now and then, but we were going through different things and, well, who knows why? But about 3-ish years later, we reconnected via Facebook and ever since we have been inseparable. Well, in our hearts at least, she lives 300 miles away from me, but we talk every few days and we visit each other.
Sometimes a friendship has to go through a growing period and separation. Not to sound too cliched, but if you guys somehow reconnect in the future than you know you guys are pretty much friends for life. If you feel like you really need her in your life and are only thinking of letting the friendship go because you are in this uncomfortable patch- talk to her about it! Don't let a dear friend go for anything less than a extremely good reason. Great friends who stay through the roughest patches of your life are hard to find.
It has been 7 years since my friend and I have reconnected and we are better than ever. I hope this helped a little.
Good luck!