My choice?

Alone i walk, and alone i choose to be
alone i wonder, alone in a sea of people.
happy people,
people free of my plague.
my thoughts constantly moving,
jetting around as the thoughts of a mad scientist.
my head in schambles,
as my feelings rage through me
every second of every day, 1000 things racing through me;
and alone i wander,
clueless as to how to deal with anything!
and alone i choose to be?

who am i?