We must have the same sinus infection! I finally convinced the doctor to give me a prescription for an antibiotic; feeling better already. She also suggested Mucinex-D (have to sign for it at the pharmacy); it doesn't dry your sinuses, it helps move things along to prevent infections.
As for Claritin, I swear by it! Been on it for years. Actually, the last few years, I found its generic counterpart, Loratadine, at BJs Wholesale Club for a tenth the cost (no kidding on the price!!). Between it and allergy shots, I don't do too badly but it is rough in the Spring and Fall.