About Cetirizine Hydrochloride?

I usually get the hay fever 3 time a week and I will take this tablet (Cetirizine Hydrochloride) from Zyrtec.
Is this normal? I asked the pharmacist she said some people take the tablet everyday to prevent hay fever. OMG, that sounds too extreme!!
Would it be harmful if you take it everyday?
Is there any harm to organs?

Cheers!
I just can't stop sneezing...