How do I (M22) move on from my girlfriend (F21) and best friend of 2 years

She was my first relationship and my closest friend. I was with her for two years. She got me exploring the city, going outside.. FOR FUN! She exposed me to social events and got me more active in social media. We watched TV, listened to music, and just talked about our days. We were best friends.

I'm not NOTHING without her. I'm in my final year of University with good grades. I have a part time job and held an internship (which many people in my program did not). I have "achievements", but they feel so empty without her.

We weren't codependent on eachother. We could go for week or two without contact because of exam time. I don't know how to feel right now, because unlike during exams she's not coming back when the two weeks are finished. There is no "thing" to finish.

My friends are busy with jobs/school, so I can't really get them to "distract" me. And none of my usual hobbies are helping. I'm not yet comfortable being "outgoing"by myself. And I don't feel enjoyment from the usual exercise/video games/programming.

TL;DR: My life feels so empty without my first girlfriend and best friend, who I was with for 2 years. How did/do you move on from someone who changed your lifestyle for the better?