One of the things that made me start wondering what was wrong with me was that, sometimes, when I was given a corrected exam at school, I wouldn't remember having taken it, and sometimes I'd notice a different handwritting. This still happens to me, and sometimes while I'm co-conscious (I guess) I sort of realize I'm writing in a handwritting very diferent to mine...
Also I'm a very "contemplative" person and after thinking whether to do something or not for a period of time, I'd realize "I" had already done it.
Tom