Dear Jen,
it sounds like you have already figured this out, since you know the active ingredient... just in case...
diphenhydramine DOES indeed interact with MAOIs ... the problem is not just that the MAOI will cause increased sedation but overall central nervous system depression will be magnified... this includes risk of respiratory failure.

we don't want that!!!!
i am really surprised it is not on the box or on a leaflet somewhere... this is usually a "do not take if you have taken a MAOI w/in x time period" type drug...
please, if you don't want to talk to the doc i understand, but at very least talk to the pharmacist about it first.
i am very concerned here.
~ waves ~