Dissapointment of myself.

I been told by my best friend.. he can be consider as my brother as i can say that he is one of the closest to me compared to all other of my circle.. he takes care of me everytime i got into trouble and always look out for me to see if i have done any mistakes and come telling me the problem.. he is one of the them which really accepts me fully for what i am and really have the patience being my brother.. i can just go to him and tell him my problems and he is always there for me to let myself out whenever i want to.. then it was that night where he and a few friends went together with me to the dinner.. we sat in a table together.. and it was one of his friend's birthday.. and so happen that i did not know it was his birthday.. and he said to me that i was behaving very childish and his friends were not happy with it.. he said that i spoiled his friend's birthday.. seriously it was not my birthday and i acted so childish and made them unhappy while that guy has only this dinner to celebrate his birthday nicely.. i feel like im the factor why he did not enjoy that night.. im just thinking about this matter the whole day and i cant seem to find a solution to make up to them.. seriously.. it was a dissapointment.. a real dissapointment..