The symptoms you describe happen in all viral infections, so antihistamines such as cetirizine
10mg or loratidine
10mg AND Calpol
650mg for 7 days should be enough until you develop the virus specific antibodies
and clear the infection.
Recurrent viral infections can be a mimic for allergic rhinitis
or allergic rhinosinusitis, so it is important that allergies to house dust mite, animal dander, moulds etc are excluded. This can be done by blood tests (specific IgE) or skin prick tests. The treatment options and duration will then be decided as per the results.
You should also get a complete hemogram, LFTs, CRP, urea and electrolytes, IgG IgA IgM levels done to see if the immune system is working. Functional antibody tests are difficult to get done unless you have access to a good lab.
I hope this helps.