Just a few thoughts-
If the anti depressants were / are not working then why not try to come off them?
The tests may give you a rough idea of your levels , but unless they are sky high or really low if you are peri then they may not tell you much.
I think you are on quite a high dose?There is the option to start a bit lower and work your way up?
It does take 3 months to bed in , I nearly gave up initially and cried every morning , but slowly it improved.
Try belly breathing and relaxation , which will help calm your nervous system.
Check your B12, Vit D and Ferritin is optimal.
Look at taking Magnesium ( not oxide) better you does a spray- this is a calming mineral, and most have deficiency.
Is there an NHS meno clinic you can be referred to?
I do feel for you- the out of control panic and anxiety is the worst.
PMxx