If i go and buy an over the counter antihistamine can i take that as well as fexofenadine?

Before taking them I was fine.By the end of those 6 days, I was suicidally depressed, anxious, jumpy & feeling thoroughly mentally messed up. I thought I’d gone certifiably insane until a nurse friend of mine told me that Fexofenadine could be doing it. I stopped taking it immediately & returned to normal.

Last night I had to go to a friends house and they have cats which I’m allergic to. Usually I leave there with blood red eyes, choking, wheezing and feeling like crap.I didn’t want to be sick as it was Christmas, so I took one tablet and hey presto the next day my head is a total mess. I thought I could get away with one but obviously not.

Medical sites in the UK&US warn of these symptoms but no Australian(I’m in Australia) sites mention it.
I’ve also found instances in the US where people have been hospitalized with psychosis after taking it. Even the leaflets given out overseas with Fexofenadine mention these symptoms. But NONE of the doctors or pharmacists I’ve spoken to here acknowledge this. They keep saying that the old fashioned antihistamines caused those problems but that Fexofenadine is ‘new and improved’ and has few if any side effects.

Has anyone else here had a problem like this with Fexofenadine? Why are these side effects know of overseas, but not in Australia?