How to overcome that someone can't forgive you?

I overreacted with him because I was worried that he forgot my birthday. He got angry, I got panicked, and even if I tried to explain and try to apologize in the process, and at the same time express that my error was to expect him to remember my birthday like I did with his, he was still mad.

I have apologized, and another one counting today via Whatsapp, and maybe that was too much, but I tried my best, and I know that if he can't forgive me, then that's all, the ball is on his side of the court now, and I have to accept that I lost him forever.

However, my emotions are getting the best from me again. I saw he has received my messages in Whatsapp, and that should be enough for me, that's what I told myself, but now I want more, I want him to answer me. And maybe very deep in myself, that he could tell me something like "Don't worry, it is ok, I can understand you" or "You are a liar, a hypocrite, and I don't want to contact you anymore, you are not worthy as I though", but the second would make me go into a big depression and make me feel that the world is ending.

What can I do to stop worrying and assure myself that I have done my part in my apology, stop thinking too much about it and don't do anything more or you will suffer?

How to overcome that someone can't forgive you?
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