How can I stop embarrassing myself?

It feels like everyday I make a fool out of myself by doing something dumb/embarrassing/stupid. whether it is dropping something, stuttering over my words, saying something dumb, bumbing in to something, i dunno i just feel llike a bit of a tw*t most of the time. and so whenever i do something silly i always sigh and think f*ck my life or i make a remark about what a total nob i am in my head. I know it's having a negative effect and i want to know how to stop it.