Seasonal allergy is one of the common ENT problems. You need to get your nose examined from an apt ENT specialist, he might recommend you steroid nasal spray and some decongestants. Drink plenty of warm water and do steam inhalations two to three times per day. Any more doubts you are welcome.
Colds and flu are a viruses. They run their course and are over in about two weeks maximum. These sympgtoms are more likely to be a form of rhinitis - either allergic or non-allergic (climate change, other irritant), or acid reflux.
As OHNS2010 suggested, you need to see a doctor for an acurate diagnosis and effective treatment.
Take care and feel better.