Why cant I forget her?

Recently due to some stupidity on my part my friend has stopped all conta t with me. We used to talk all the time. Now no more. I used to work with her and due to me not taking my meds I had some serious highs and went off on her. I feel so guilty for doing it and would love to go back and apologize for it but I am nervous right now may not be the time. I can't forget this and its knawing at me. I realize my selfishness and want her to know that that's what I was doing. I'm not wanting anything in return so how do I let her know that