Without knowing what you were taking Benadryl for, it's impossible for anyone here to recommend an alternate. Your best bet is probably to talk with your personal physician or pharmacist.
I can tell you, though, that if you were taking Benadryl for allergies, it's not your best choice anyway. Second-generation antihistamines, such as Claritin, Clarinex, Zyrtec, and Allegra are just as effective and don't cause sleepiness. There are also nasal steroid sprays such as Nasonex and Singulair.
Talk with your doctor to find out the best alternatives for you.
To your health,
what reactions would be present if allergic to benedryl
This is a question for your Doctor.