Hi welcome to Healthc are magic forum.
Thanks for calling H.C.M.Forum.
After 4 days of the period started spotting, intermitently, doctor advised
naproxen , today you have started with stomach pain,
tiredness.
Naproxen is an irritant of
gastric mucosa to some people. It might be the reason for that.
I advise you to consult your doctor for followup. You may need to have PPI, and some supporting drugs for relief of the pain, and weekness.
The reason for spotting could be infection, or
anaemia, if it is repeated you can consult a gynacologist for diagnosis and treatment.
Wishing for a quick and complete recovery.
Best regareds.