Since fexofenadine (Allegra) isn't helping, you might try switching to a generic corticosteroid nasal spray like fluticasone propionate, which is highly effective for a stuffed nose, sneezing, and itchy eyes. For your severe sore throat, generic pain relievers like ibuprofen or acetaminophen can help ease the pain. Simple remedies like warm saltwater gargles and honey can also bring great comfort. If your sore throat worsens, is accompanied by a high fever, or doesn't improve in a few days, please see a healthcare professional to ensure it isn't an infection.