Allergy Test - failed due to meds

I'm a 43 yr old female and have developed what we are 99% sure are airborne allergy problems. I am on quite a few meds for other health problems. I "flunked" an allergy test today and the doctor thinks it was because of meds I take for psychiatric disorders - either Zyprexa or Xanax. (By "flunked", I mean the control didn't react). I am currently in a time of crisis and even though I had looked up these medications and quizzed the staff extensively prior to my appointment, I was unaware that either of those were considered antihistamines or had antihistamine properties. Has anyone else had a similar problem with "hidden" antihistamines?

I had a horrible week making sure all other antihistamines were out of my system, wearing a surgical mask outdoors, etc. so I could get the testing and will now have to reschedule. Can anyone suggest a good, reliable and user-friendly website that might list all possible medications to avoid? The doctor I saw was not sure which medication it was. She was suspicious because it was an "ine" ending. I know almost nothing about any of this. I want to get the test sucessfully completed because my hope is we can start treating this with injections ASAP.

This has been going on since September 2008 and I strongly suspect it is related to pine trees. I'm on heavily wooded acreage, so the sooner we deal with this, the better. I guess the good news is that I can take antihistamines for a few days. :-)

Thanks in advance!!!