It just seems to me that everything is worse at night. Maybe its becasue youre not distracted witht the goings on of the day...being alone with yourself can really stink. For me anyway.
Are you on any meds? Maybe there is something that you take in the morning that wears off at night? Or do you do caffeine at dinner? Is there any times it doesnt happen? Maybe if you start a journal you could figure it out...Maybe its just like a habit?
I get that way when Im depressed...during the day I mope and then at night Im like you described...Its like I get crazy from sitting in the house all day and by night Im a time bomb. When I go to work and stuff it doesnt happen..