Boyfriend issues 🙄

I’ve been dating this boy for a year and it’s the best relationship I’ve ever been in. We didn’t do petty shit and we talked every day and I’d see him on the daily and I’ve met his parents and he’s made me so happy. But he had to go away for college and I don’t know if it’s worth keeping. I feel like he’s too busy and I start feeling like he isn’t trying as hard and now when he gets annoyed he hits me with a “ok” or i get left on read when we used to be so open about everything. I won’t see him until December and I’m just getting angry because I have mentioned it to him many times about how I feel and he just says im sorry but doesn’t really change anything. I don’t know if I’m being crazy or if I have good reason :(