I'm not sure if I have the answer to your problem, but I do know that what you feel is what you feel, and that's it.

Even if you don't want to feel bitter, you have to accept that in that moment you in fact DID feel bitter. There's nothing wrong with that, as long as you acknowledge that while you may hold some resentment, you're going to rise above these feelings and that the you that you are proud of is a person who would accept a situation like this and make the best of it.

Best of luck.