Thank you for your query.
I think your weight gain is due to quetiapine
tablets that you are taking as weight gain is a known side effect for this medicine . Pregabalin
does not lead to weight gain . Plus depression
might add to your woes of weight gain .
You should consult a psychiatrist
for change of your prescription and start the drug which suits you for depression.
Hope you are satisfied with the answer.
If you have any further queries feel free to ask.
Wish you good health.