I hated it & the person it made me become.
Took me a couple of weeks to get into my system, I lost my appetite, weight & quite frankly my marbles. I look back at that time & could weep at the pitiful creature I was.
Took me a good couple of months to get off it - electric currents would ping my head out of nowhere. I insisted DH move the wifi box because I was convinced that was the cause !
I suffer from anxiety too & am agoraphobic. I frequently have to sit myself down & challenge the thoughts & look at close friends & wonder if they are thibk the same, which helps me workout what is rational & what isn't.
I've been to my dr & have CBT thing (but haven't done it yet). I also carry rescue remedy (helps me even if just by placebo) & somewhere I have betablockers in case I do have a panic attack.
The 'drug' that made a massive difference to me was 5HTP. You can buy on Amazon & it's basically a serotonin booster. May stimulate you have vivid dreams, but no nightmares. For me (& other people who have tried it), I would say it saved my sanity.
Also true ref the vitamin d deficiency but I understand you need to look into supplements. Magnesium is a good nerve calmer as are B Complex vitamins.
Hope that's helpful.