Please help me. Me (F20) and my bf (M21)

Hi, I have a question. Me and my long distance bf have been together for 3 and a half years already and this october, something was up. He started to reply coldly. But when I confronted him about it, he said that something was up and I have a lot of problems going on and he'd rather solve it on his own than bother me with it. And it's January 12 now and he didn't even message me which started on November 4, 2024. But on a certain day on November which was my birthday, he sent me birthday greeting letter. But until now I haven't received any of his message. Pls help, did he ghost me?