First, stop using Nasivion immediately. Using it for more than 3-5 days causes rebound congestion, which severely worsens nasal blockage. For safe, long-term relief, switch to a prescription steroid nasal spray (such as Fluticasone or Mometasone) to reduce inflammation, and use an oral antihistamine (like Cetirizine) for sneezing. Daily saline nasal rinses will also help clear allergens. However, because your deviated nasal septum (DNS) structurally blocks airflow and affects your sleep, medications may only offer partial relief. I highly recommend consulting an ENT specialist to discuss septoplasty, a minor corrective surgery to permanently resolve the structural blockage.