I was in the best period of my life

I was in the best period of my life The last Three days has been absolutely fantastic. I have had two presentations in front of my class which went great. I have been much more outgoing, and made a lot of new friends. I almost didnt stutter at all. I talked to strangers, and decided to hit the gym at primetime. I talked to a girl there for a bit without a hesitation, but then BOOM. I blocked so badly on a word. I have never had a block so bad i cant get the word out before. It has maximum been 4-5 Seconds, but i just couldnt get the word out. And from there on, my confidence is now back to zero and i feel like shit. How do you guys maintain these "good periods"?