Hayfever problems

I dont usually suffer with bad hayfever, but for some reason it has been very bad this year - not much sneezing, but general tiredness, runny nose, breathlessness and low level fever. I thought I was having mild case of COVID-19. Apparently, it can be mistaken for COVID-19 my GP told me. I suddenly lost a fair amount of hearing in one ear. GP found no wax but what she did find was a sort of flap in the middle ear which I believe is associated with sounds etc had gone flat. She said air pressure could have caused the loss of hearing. I had been taking Cetirizine hydrochloride and Beconaise nasal spray. She prescribed Fexofenadine Hydrochloride for two months. I have taken it for nearly three weeks now but for the past two weeks I noticed I get uncomfortable feeling in my stomach and have been having loose stools. Has anyone else here experienced this sort of side effects or any other side effects. I also take inhalers. I am wondering if I should stop taking it or wait till I speak to my GP.

I’ve been on Fexofenadine for 4 weeks and it gives me an awful metallic taste in the mouth