i'm graduated from high school and i was diagnosed in 7th grade. i had the same issues. i many close friends in 7th grade until i was diagnosed with diabetes. after that, nobody would hang around me. i lived in texas at the time. at the end of 8th grade, i moved up to iowa where i live now. i had some friends here and there until i got a real close friend. anyways, he became like a brother to me, but around my junior year, we started fighting and we hated eachother all of my junior year (he was a year older), when i was a senior he went to college (still hated eachother. he and i hadnt said a word for almost two years, just until about a month ago. he and i hung out and we talk more now that we are both older.
what i'm saying is that time will heal wounds as well as open up new ones. you will make friends and hang out with other people and find other things in life that you will enjoy without the presence of your best friend. it may not seem like it now, but you will find things that will make you happy. think of the other persons feelings as well. maybe they will be upset that the two of you can't hang out anymore. it can be hard on both of you. but if you guys stay in contact with eachother, i am willing to bet all will be fine