Random functional unexplainable blackout

For as long as I would remember I have had these times in my life where occasionally I would "black out" or something. There are no signs of when it will happen and they usually last anywhere between 2-10 minutes, according my roommate it just depends on the situations at hand, like what sort of mood I'm in or if I have been active or not. After so many years of this I've gotten to the point where I'm not scared when I notice I'm somehow in a completely different spot then I was half a second ago, it's sort of just normal. Only one other person knows about this because I'm still scared to tell anyone else due to the fear of being mugged or robbed while blacked out then the same person that robbed me come back and act like they just want to help me. My roommate said he can usually tell by my behavior when I'm blacked out, I tell everyone else that notices a attitude change that I have depression which isn't a total lie but it's always exaggerated a bit to make sure no one gets suspici