"i am taking mirtazapine for anxiety for the past 5 months now. after 3 weeks of start of this medicine, my anxiety was gone until couple days ago. all of a sudden i started getting anxiety attacks and palpitations. it feels like the effect of medicine is gone. i am seeing my doctor in a week and lets see what he suggests. currently taking xanax to control my anxiety. 
i have experienced that whenever i have anxiety, 5 minutes of workout (treadmill or fast walking) it does help relieve my anxiety. try it."