Dengue IgM test should only be done after 5 days of fever. Dengue NS1 should be done in first 5 days better if done after 24hrs.
You should take plenty of oral fluids ORS and paracetamol 500mg thrice daily.
Feel free to consult if you have any queries.
Next Steps
you may refer my article on dengue for more information.
"Dengue Fever : Don't Panic, Know How to Deal With It" by Pratyush kumar mishra - https://www.practo.com/healthfeed/dengue-fever-don-t-panic-know-how-to-deal-with-it-29261/post