Long term use of SSRIs ( zaptra in your case) can case some weight gain which may indirectly contribute to
diabetes.
You can discontinue medicine by slowly withdrawing them, but as you are using these medicines for longtime, withdrawing your medicine may lead to recurrence of original problem for which you are using zaptra and Ativan.
Next Steps
better to continue your medicine+ start treatment for
diabetes and focus on lifestyle modifications. Do consult your psychiatrist before discontinuing your medication.