How to deal with this grief?

[Angelica]

I think if you really loved her you would want her to be happy. She is happier with someone else. It is up to you to let her be and remember her fondly and let her go. If it hurts to communicate with her now then don't. It is not about her choosing the better man, just the right one for her.
Congrats on getting accepted into the program... now get to work. It may be hard but you can do this. People believe in you, otherwise they would have accepted someone else for the Program.