Please don't think that I am trying to minimize your symptoms or your experiences but honestly it sounds like your burned out. I was told once that grad school will make you lose your dignity and your will to live.
It may be time to take a break. Go get some experience in the field. Refresh your mind and find something new to focus on, or something you can add to your research.
If you are not comfortable with putting your plans on hold maybe you can discuss what you are going through with your psychiatric provider and identify whether or not they can provide you with some sort of long term anxiety medication. I would also suggest getting involved in some sort of group, whether it be for those with anxiety and irritability, a bipolar disorder group or just an ukulele playing group or an origami group. Just something not school related.
FTR I am speaking not as a psychiatric provider or counselor, I work in behavioral health as a case manager and you should take your doctor's advice and what your gut says over anything I say.

Good luck.