Yup,it's definetly the protein.I have also had trouble going to sleep for the past few days as well as waking up tired and groggy.This reminds me of the time i would drink 5 large shakes a day, i also had the worst case of insomnia i have ever had in a long time.It was also a time where i was semi-addicted to Unisom,the sleep inducer.I had to take about two a night and it knocked me out,soon it only got me high and nothing more.To think i was gonna go back to using them again! Actually,the higher Sugar ones are actually less stimulating then the high protein ones,at least with the sugary ones the excess Sugar has a potential to be burned as fuel where as the excess protein just gets wasted since you can't store aminos like you can glycogen.