I (20M) go to college 9 hours away from my home state where my girlfriend (19F) lives. We started dating over the summer and have kept our relationship running smoothly through the fall semester. Winter break has been the first time we’ve been together for more than a week since college started in August. I leave to go back to school on Sunday meaning that today (Friday) is the second to last day we’ll have together before we have a week for spring break. 
Her best friend (19F) invited her over for a girls night tonight and my girlfriend agreed to go without talking to me. Normally this wouldn’t be an issue but I can’t help but feel offended because it’s my second to last day home and she’s spending time with her friend who goes to school 30 minutes away and neither of their winter breaks end for another 2 weeks. I told her that I really wanted to spend the night with her because we only have a very limited amount of time left and she could see her friend after I left but she said this was something she really wanted to do. She reminded me that she rarely sees this friend despite how close they were in highschool, however, that doesn’t seem like a good reason to me because if they really wanted to see each other more often then they could do that with minimal effort. A more valid reason she gave me was that we’ve been spending almost every night together lately, which is true, but it still upset me because after tonight we only have one more. She clearly felt bad that she upset me but it didn’t change her mind about going to spend time with her friends. I don’t want to seem clingy or controlling but I really feel upset she didn’t make me a priority when we have so little time left together. I’m even more mad because I feel like I have to suppress my feelings so I don’t ruin our last day together. AITA offended that she didn’t make me a priority when after tommorow she won’t be seeing me for months?
TLDR: I’m upset with me long distance girlfriend who spent the night with her friends, who live in the area, instead of me on our second to last day together until Spring Break.