My stutter is getting worse.

My stutter is getting worse. I don't know why but I'm stuttering more than ever and it is affecting my personal life. Last week I had a presentation and i couldn't utter a single word, it was so embarrassing, people laugh when I speak because of it i stopped talking with any one, I couldn't even say my name at Starbucks. I'm getting depressed because of it and I started smoking, I don't know what to do with my life, I lost hope.