Lost Myself !

My brain cells got damaged ! I have become less efficient and very slow. Was just trying to analyse why all this happened ??
I was pretty fast in my work and very efficient. I felt more confident, focused and motivated. I could maintain a balance between my professional and personal life easily. I kind of had a fair idea about what I am doing and what I want to do. I was one of those enthusiastic persons who are always ready to go !
Due to some unfortunate circumstances I went through a very tough period for around 6 months. That tough phase has ended and I am happy finally. But I think it has done heavy damage to me. I feel very ordinary, the confidence I had has come down.
I am not sure if i will ever be the person I was, I do not know if I will ever feel superb about myself.
All this does not upset me but makes me very thoughtful sometimes. I feel lost at times, and wonder about where this life is taking me.
Just want to know from you experienced people out there if this is normal and I will be fine OR will it never go ? My dreams are still unfulfilled, I want to fulfil them but I lack the enthusiasm I earlier had. Sometimes I am ashamed of myself :-( .
May be I could not explain very well my situation but if I have to say it all in a line I would say that "I have lost myself !" . I want to get back to my own self !