It didn't take me months to figure it out (not OP), you might get some insights quickly. Get one of the fitness trackers(Fitbit/MiBand/apple watch) and wear the watch for a week, then take a note of the things you're doing in the evenings and see how if affects your baseline from the previous week. For me, exercise was a clear winner on the first day - I spend less time awake in bed, sleep longer and higher quality _every_ day I exercise. Others, like working late, or playing video games late took longer to figure out.