Hi. I Am Currentĺy Suffering Anxiety Attacks As Soon As

Hi.
i am currentĺy suffering anxiety attacks as soon as the daytime turns into night.
i dont know what it is about the dark outside that sets my attacks off.
my doctor thinks im depressed.
I dont feel depressed.
been prescribed citalopram and beta blockers.
i stopped taking both after two weeks.
Citalopram caused severe agitation and the beta blockers bad headaches.
help me i feel helpless to control my anxiety attacks.