Anytime I get overly angry or upset I tend to black out and either hurt myself or whoever's around me..

Yesterday during an argument with my boyfriend I blacked out and the next thing I knew I was holding a mug handle and there was blood and glass everywhere. I freaked out and assumed it was coming from my head but thankfully it only bruised there and cut my pinky finger. 

Once it hit me what happened I had a complete panic attack and just kept thinking I was thankful it was me that got hurt and not my boyfriend.. I think he could tell how terrified I was though because instead of dealing with my cut and bruised head (which he was trying to help me with) I was trying to back away and tell him to leave so there's no chance of me hurting him... but he managed to calm me down enough to deal with the cut.

Is it a common thing to have these sort of black outs and not remember doing something so ridiculously stupid? Does anyone know how to take control of this?

The most frustrating part is that yesterday was one of my best days in a long time until that happened... This feels strange to say but it always seems as though this darkness inside me feeds off my happiness... The better my days are the harder I crash.