hi, pharmacist student here. the only prescription only drug is desloratidine CLARINEX. The rest can be found in equal strengths over the counter (loratidine, fexofenadine). These drugs are all second gen antihistamines i.E. they work their effect without causing as much drowsiness as first gen antihistamines. First gen antihistamines are : benadryl diphenhydramine, chlorpheneramine. These drugs are actually stronger than the first generation in my opinion. These first generation antihistamines are available over the counter. But they cause drowsiness. They are not offered as prescription only.
So there really is no "prescription" stuff, that you talk about. The only incentive to get some of these as "prescription" is so your insurance will pay for it. If we get a "fexofenadine" prescription im going to run over to our over the counter products and open a bottle of allegra to fill your prescription - and most pharmacies do this.
As for your symptoms being hard to control: i suggest you take cetirizine ZYRTEC. But you have to take it prophylactically: so 2 weeks before you think allergy season will start. Then take it everyday until allergy season is over.