In this pandemic times, I don't think any doctor will give medically fit certificate without getting you tested for covid but still try to reach some nearby local doctors and see if they can help u. But I would say this is wrong, because even if you get medically fit certificate, and if you are infected with covid, your office colleaguea are at risk if you go to office. So be a responsible person and get yourself tested for covid, if it comes out negative you can have symptomatic treatment and continue going to office.
Next Steps
get a covid test done on 3rd day of symptoms.
Health Tips
wear double mask and mainatian hygiene