Why do i always do Stupid sh*t?

i always do stupid **** and now i got people thinking the wrong **** about me.. i know this isnt serious and im overreacting but i feel like im gonna always do stupid **** and im neva gonna be nothing. i dont know who i am, i worry about what people think of me, i cry and complain over small things im a coward. i know this sounds stupid and people probably arent thinking about me or what i did but i dont want people thinking the wrong things about me i used to say things like im ugly or lame for attention and i dont think i even meant any of it and im real quiet now i wasnt even shy and people think im afraid of talking to girls or whatever, i know theres nothing wrong with it but i dont want people thinking of me as a pussy or a coward. i kinda brainwashed myself to care what people think alittle when at first i didnt care.. this sounds stupid i know but i really do need help on what to do. i know if dont want people thinking a certain way then why did i say and do stupid ****