As with all medical conditions, if you cannot get the symptoms under control within two days or are in distress, you should seek professional assistance. For people with diabetes, that includes maintaining glucose levels in the target range. Ring your GP and await a call back as they are currently very busy.
Specific to COVID-19, if you have the flu like symptoms, contact the HSE helpline 1850 24 1850 for advice specific to the area of the county you live in. You should not attend your GP or hospital as you risk spreading whatever illness you might have.
More information on https://www2.hse.ie/conditions/coronavirus/coronavirus.html