I would think that it may look bad riding at only 12 hours so I would definitely add another course. Pharm schools actually do pay attention to your courseload (# credit hrs per semester or quarter) because they really load on heavy schedules in pharm school and they want to make sure you can handle it.
However, OChem, Physics, and Calc are tough enough on their own so I would not want to tack on Genetics but it is entirely up to you. Yes, you know your abilities better than anyone else but you probably have no idea how well you can handle this combo of classes so I would bet on playing it safe. OChem usually consumes people's lives since it is a dramatic change of pace from GenChem. I would take Gov since it's typically an easy class that is required at a lot of undergrad schools. Generally true rule of thumb = the more people at the university that are required to take a particular class, the easier it is (they can't fail everyone).