Flying

Around 6 PM, I usually sit down and go on the computer. Whether I am being productive or unproductive, I always end up descending into a deep sorrow as the night goes on. Why does it feel as if my thoughts descend into such negativity? I think they are realizations. When I have time to relax and reflect upon my situation, day time activities are not there for me to burrow in. There isn't external stimulus that allows me to forget about my problems.  Everything that I experience at night is usually from within myself.