What Causes Mood Swings And Depression?

Hi. recently I ve been experiencing a lot of mood swings that range from either me feeling extremely high, POSTIVE and pumped up, or me feeling extremely low with very, very short periods of normal mood in between I feel like I am the cause of everyone s problems, like everyone is unsafe around me because my sudden fits of anger and aggression where I feel physically destructive. I hate feeling crazy and so all I do during these phases of anger is cry, because of the amount of anger I feel and I feel very guilty for the same and it s not treating me very well. I have random fits of extreme aggression that have no explanation and at times I am so pumped up physically, that i feel like everything is just moving way too fast – my hands are shaking and my heartbeat is racing and I jump from one thought to another very quickly. Please tell me what the problem is and how I can rectify it