Has it been proven that the drug Lexipro given for depression and anxiety really takes 30 days to work?

I took my first dose of Lexipro yesterday, and it gave me such a keep I couldn't stop smiling , I was just happy all day, It took me a while to fall asleep , slept for a few hours then I was wide awake again at 430 in morning and not even tired. I know it may seem as though its all pyschosematic, but I know my body and I was in overdrive yesterday. I took my dose today and don't seem to be as up as I was yesterday.