Breakdowns. Please help

Dj

Idk why but once a month I have a complete mental breakdown. I tend to keep my feeling to myself because I HATE putting my problems on to other people. Ik I have ALOT of built up emotions but I cant bring myself to talk about it. But anyways I breakdown to the point where I just cry to the point where I’m gonna pass out and I hit my sometimes to try to calm myself down. And then other times I just wanna let go, and hope that I can just take one breath be gone from this world forever. And it’s gotten to the point where I’ll take my mom medications to try to get away from it. And another time I was driving and I wanted to just close my eyes and just let the car go wherever and not care, and i In fact ended up doing so, but last minute I opened because I didn’t want to hurt anyone.And after a day or two I’m fine back to my normal self perfectly fine. I don’t know what wrong with, and I don’t know what to do