what should i do in order to be normal again?

I cant do the stuff I used to do anymore, I'm always crying without a reason, I tend to overthink a lot, idk my self anymore, I'm not the person I used to be, I tend to get mad at people without any reason, I get annoyed easily, I'm always lost in my thoughts, I tend to have nightmares where everything is my fault, I cut my self, I feel empty... I smile because I just smile, I laugh cause I laugh, but I'm never actually happy. I don't know what this is but I want everything to end here.... if only suicide was not a sin I would be dead already