Yes, it sounds like you are doing all you should. Have you considered the changes in air you are breathing now, in these cold months of winter, might be causing these problems. For instance, the heat source of the home you are living in, with additional dust blown from ducts, fireplace fumes of burned wood, kind of fuel from furnace, etc., etc..... in Florida, perhaps, you've not needed additional heat, however, seems you mentioned how very cold it became there. Cranking up the old furnace, and unused duct -work might be spewing out who knows what??? Just keeping windows and doors closed to keep out cold, might be keeping in an irritant. Addionally, have you considered fibers from extra blankets/sweaters/afghans, etc.?
A new animal of some kind? Their dander can play havoc among those with allergies, maybe has same effect on you?
I don't mean to be consenscending.
You most likely have considered all the above.
You know how I feel about prayer.
I also believe, be it His will, those who are ~truly~ Christian, can do hands on healing of themselves in the name of Jesus, the best Physician and healer in the universe.
I pray for your relief as I write this. I do believe in miracles, be it His will.
Hugs and love, Pat
..without surrender, be on good terms with all persons..