You can take zyrtec, i used it through three pregnancies, doc okayed it, kids are healthy.
Inhaled medication would be preferable along with environmental avoidance of known allergens, if that will control your allergic symptoms. In general, the evidence suggests that antihistamines are safe but my advice would be to avoid taking any medication, unless absolutely necessary for control, especially during the first trimester.
Also, you should not take any medicine, conventional or herbal, without first discussing it with your physician.
Good luck