Doctor perscribed CITALOPRAM for my anxiety?

I searched on the internet about it , it says its used for major depression, now im scared to use it, i told her i have a lump feeling in my throat that hasnt went away for 3 days, and i have troubles with panic attacks and anxiety/depression anxiety caused by scared of dying and i worry about my health too much, i dont cry alot when i did cry it lasted an hour and the lump feeling in my throat started. idk how anti depressants work and ive never used them , this is the first time ive went to the doctor for my anxiety ive had it for 3-4 years on and off , i only found out that i had anxiety 2 months ago ,seems to have made it worse, i dont feel anxiety a whole bunch right now, it starts feeling worse when someone tells me some thing, please help me :(