you're young, and it may seem like it's impossible to make new friends, but sometimes it only takes a simple hey can i join you for lunch or hey want to come my house and play xbox to make a few new friends... there are
always "loners" at school- those people that feel like they don't fit in & have few or no friends- i can guarentee you are not the only one. although it's really tough to have your best friend move away, it's good to branch out on your own (hope you guys still keep in contact- because i'm sure it's going to be tough too for him to be in a new school)
I've had lots of my closest friends move away- my best friends from kindergarten, 3rd, 4th, and 5th grade all moved away, and i never heard from them since (this was in the time before the internet lol). but in middle school, i met my bff whom i'm still friends with (and im 23)
(i also went to a middle school where i 99% of the kids did not come from my primary school- so that was tough at that time too)
school is a unique experience- you will not be surrounded by so many people your age everyday like that in adulthood. It may be a good idea to check out some clubs/after school activities that you've never tried before to mingle in some new circles.
every school year is new chance to reinvent yourself- you will see people who used to be really popular fall back and become really unpopular, and you'll see the opposite happen too.
i just wish wish wish i could go back and change a lot of the stuff i did when i was a teen- but i can't. you have the opportunity to make a change, and say no im not going to let life pass me by.
pass a note saying hi to the person next to you, ask people how they did on tests, or ask to borrow a pencil- it sounds corny
but if you want a friend, be a friend. (meaning just be nice to somebody on a somewhat consistent basis- not stalker though

)
and if you feel like you are really struggling or having issues, you could probably talk to the school counselor- they are paid to help out kids with whatever issues they have, but i know some counselors are kinda annoying as hell so idunno, but they are there.
hope that helps!