Pls someone tell me why i feel this way

Hi, i have had a long history of feeling allright for a long time but then suddenly losing my shit I cant help but to overthink EVERYTHING. I am mean to People i dont wanna be mean to and i feel like i dont have a purpose in life. I want someone to talk to but not someone ik know because i am afraid that they will judge me, sometime i just dont know what is going on with me: i feel sad without having a reason to be sad Pls help me sorry if the post is weird i dont really know how to express my feelings