Hello and welcome,
Bad breath may be due to the -
Poor oral hygiene
Nasal discharge which is mucous in nature.
I would advice you to visit a dentist
and get thorough scaling done.
Use soft bristled toothbrush and chlorhexidine
mouthrinse to gargle.
Also visit an ENT specialist
and get the treatment required.
Get your blood sugar level monitored.
I would advice you not to take medicines without medical supervision.
Hope this helps.