<human>: Can you give me a shortened version of the text?

Me [17] and my girlfriend [18] have been dating for about 5 months and when we started we knew that we had to break up at the end of the summer because she was going away to college 4 hours away from me and I was staying in my hometown to finish high school.
A few days ago the time came for her to go and we said our goodbyes and what not and left it at that.  She was in an abusive relationship before me and I was in a toxic one as well and we slowly started to fall in love.  

Before she left she talked about all the stuff we were going to do next summer when she comes back.  We havnt really talked since saying goodbye and ive seen alot of photos on facebook with her and this boy and a few other of her girlfriends there.  Ive noticed that ive quickly began to develop negative feelings to the girl just a few days ago i thought was my best friend.  

Reddit, is this normal?  Will they go away? Should I just wait it out and see if they go away? I want nothing but the best for her but i cant help but try to avoid every form of social media shes on.
<bot>: Girlfriend left for college, want to remain friends and have a positive relationship while shes gone but cant help but feel angry at her for a reason unknown.  Is this a normal?