Lisa Marie, Eating lots of PB can be a good source of protein for you, but the type of PB is important. Avoid the standard PB brands like Skippy and Jif. Get the "old fashioned" PB.
Skippy and Jif remove the valuable peanut oil from the PB and substitute other oils and fillers to make it smoother and non-separating. Peanut oil is one of the 'good' oils.
Old fashioned peanut butter leaves in the peanut oil, so it separates if it isn't stirred up and kept in the fridge. I think Laura Scudders and Smuckers makes old fashioned PB.