What am I feeling? I'm always extremely depressed and confused lately?

Lately I feel as though I've just lost my mind. I keep having contradicting thoughts, like I'm 2 different people and they just switch off controlling me whenever they want. I find myself constantly talking to these personalities, (so myself I guess) and just doing extremely unusual things. Most of the time lately I just feel like hurting myself, committing suicide, and just doing stupid dangerous things things. Then I will randomly feel like a completly different person and start telling myself how messed up it is that i think about suicide and hurting myself, and that I need to make a change so I can be happy in life, and then I'll go back to feeling depressed. I have no control over these thoughts and emotions, how do i gain control over them? What is this called? Is there anything I can do? I honestly would rather just die at this point because its impossible to live as two completly different people who are the exact opposite of each other.