I feel a bit unappreciated at the minute

I (18M) am about to finish exams, my gf (19F) as soon as I finish, starts hers. Weve been together over a year now. Now, she is incredibly studious I’ll give her that, but also gets extremely stressed and anxious about exams, and can suffer a bit during them. Now, it’s almost summer break too, where we’re both off, but I’m going away to housesit with my mum as one of her cousins is away and I haven’t seen a lot of my mum recently, I’m them going away with my dad, as it’s his birthday. However, I have one weekend in between the two holidays where I could see my girlfriend. Now here’s the problem, she planned to see one of her friends gigs then. This is what gets me, I was initially annoyed at myself, because I got the dates wrong, so was a bit upset I wouldn’t see her for a while, but then I said what if I come to the gig and she says no I’d rather it be me and my friends. I got a bit annoyed tbh, because I won’t see her for another few weeks and i felt like she didn’t really want to see me, I tried to make compromises, and all were shot down and she’d say ‘I just want a night with my friends’. But here’s what’s making me feel a little unwanted and unappreciated as well as that, we’re not going to see each other until after her exams, and I plan on talking to her about how she’s made me feel, because it’s not a regular thing, just recently, but she had a similar chat to me midway through my exams, I say I want to have a chat to her and she says after her exams. I feel like I can’t say what’s on my mind and hurting me until she isn’t stressed, but she said it to me whenever it suited her, and it’s starting to hurt me a bit now. I won’t see her for a while, and the one time I can see her, she basically refuses to see me. Now please, be real with me on if I’m being a bit selfish here, because I am bugged and plan on talking to her about it. Thanks

TLDR, I feel a bit unappreciated because my gf won’t change a plan to see me at the only time I can see her.