I wanted to know i took benadryl (diphenhydramine) because my allergies are acting up and i'm stuffed up, i have a cough, i'm weeding because my asthma as well. is it o?

Probably not: I presume you are asking whether it is ok to do some weeding when your nose is stuffed up and your asthma is not controlled. In general , the answer would be no since you are likely allergic to weed pollen and molds from the disturbed soil. It is also important for you to call your doctor about your asthma. Benadryl (diphenhydramine) or any other antihistamine has no decongesting action, nasal steroid does.