I Can And Quite Often Just Fall Asleep With Little

i can and quite often just fall asleep with little or no warning in the early evening, and then after 5 minutes I am wide awake and full of energy. I have an office job, am 45, wear glasses for PC work.

I have had blood tests, urine tests, cognitive therapy, and yet it still happens, probably most nights around the same time. always at times when I am inactive, if I am active it does not happen