I was arranging my taskbar and all of a sudden, all my windows
disappeared. I thought they were gone but when I alt +tab, they are
all there. The thing is they now, my quick launch area is really
huge and the 'active windows' region that is supposed to be on the
right of the quick launch area is gone (refer to picture). Please
help!!!

i think that you can just pull the taskbar down. u accidentally
pulled it up alr. and also rmb to lock the taskbar to prevent any
accidental actions.