It is less likely to have withdrawal of Nexito after this much time. You may have an anxiety episode(chest pain and dizziness).
You should actually talk with a psychiatrist about it. You can take the tablet Clonazepam 0.25mg as needed, but still take it under the guidance of a psychiatrist. You can learn to relax and do breathing exercises to deal with it.
Do blood reports - CBC, RBS,
Thyroid profile,
Vitamin B12 and Vitamin D3.
I hope that you get my point.
Please let me know if you need some help.
Thank you.