She11y, I think I might have a solution for you as your post was me a few years back! I was on everything and then some. I have the most awful allergies.
The answer you are looking for is the generic Walmart brand CHILDRENS Zyrtec!!!!!! YES, I said CHILDRENS! It is the only stuff I can take and within 3 days-BOOM I feel great and my runny nose has stopped.
I always recommend this to people and it always works for them. The look on a person's face when I say the generic children's Zyrtec is priceless
Ps...the grape one has a pretty good taste! Even my DS likes to take it!