If i am allergic to allegra d allergy medication is is possible im also allergic to benadryl?

Unlikely: Anything is possible, but it is unlikely to be allergic to both medications. Although they are both “antihistamines”, they are very different pharmacologically. Benadryl is a first generation antihistamine, and does not contain pseudoephedrine (a decongestant) whereas Allegra D belongs to the 2nd generation of antihistamines & also contains pseudoephedrine, so two meds in one. Hope that helps you!