Hydroxyzine is what I was prescribed by my allergist for my hives, which sound very much like yours.
He also said that the strongest over the counter is Zyrtec (it is much stronger than Benadryl), which now comes in a generic at stores like Walmart, etc (much cheaper). I have found that works well, too. He said once you start having an allergic reaction, it is very hard to stop it, and things like stress and anxiety can make them worse...sometimes there is no cause for the initial hives that can be discerned. He said he himself had them for about 2 years and never knew why. I had them for 2 years+ after having an allergic reaction to an antibiotic.
I highly recommend the Zyrtec...it didn't make me sleepy, but then no med really does. If you are sensitive, try it when you have nowhere to be. Good luck, I know how they suck and how miserable you are.