S/O shows no emotions

Hey Guys ..sooo my boyfriend is very cold and with very cold I mean that he shows very little to no emotions. I don't know what to do. I feel like he just does not care. For Example: I am from Germany and we have 3 different educations here (like 3 different schools that are seperated from not so good students to normal average students to "smart" students (if you can say it like that please correct me if you think that I am wrong(*trying to explain it very short*))) Anyway I am done with my finals and I have already got my "Abitur" which is like the highest highschool graduation possible here. And I am so happy because I am free and dont have to go to school anymore and reached even better grades than I wished for but he just doesn't care. He didn't even congratulate me or said anything and when I told him that I have expected more happiness or something like that he just said "Ok oh wow nice" in like the most sarcastic voice and went back to sleep. Every really every single one of my other friends or even people I don't really know cangratulated me and asked me how awesome it has to be that all the stress and anxiety is finally over. but my bf? Nothing. It just feels like he doesn't care. I have worked so hard for this the past years. PS :Sorry if my english is not the best. UPDATE: I asked him if he comes to my official graduation (the ceremony where I officially get my certificate) and he said that he doesnt know yet because he has his last final (from his job )one or two days before and he wants to get drunk with his friends and celebrate. I understand that he wants to celebrate that but cant he just do that maybe the day after my graduation? I mean it is my graduation and he doesnt want to come just because he wants to get wasted (what he can do every other day after his final) and dosent want to be at my school at 11 am.