So sorry for your struggles, know that you're not alone and this too shall pass, just like it did with your PPD.
I'm assuming you tapered with direction from your doctor. You didnt do anything wrong.
I've read where it can take some time after stopping an AD to get "normalized" again. I've never gone off an AD except Prozac & it's the only AD you don't have to wean off of so I had no issues.
I did have issues going from Cymbalta (SNRI) to Zoloft (SSRI) this year. Ended up going back on an SNRI & mostly feeling better.
Are you experiencing the winter weather where you live, lack of sun, shorter days etc? SAD could be playing a factor too. Not uncommon for this time of year in North America.
Do you take vitamins? My psychiatrist recommends 3000 Vit D3 this time of year. Magnesium also can help with moods. Had your thyroid/blood tested lately? Just some things to consider.
You'll get through this. Time to sharpen your coping skills while you're riding this wave. ScaredyCat is right that therapy is also a very important part of healing.
This is a great forum so come back here- we'll support ya on your journey back to emotional wellness. You're in good company here
Hugs!
Lisa