I don't think you are overreacting Kelly. Their sobriety (or lack thereof is their business), but it's your house, and if you feel uncomfortable with all that alcohol in your house, then you are perfectly justified in asking them to get rid of it.
Maybe nicely let them know that although you were okay with them drinking at the cookout, you were not expecting the fridge to be stocked for the week.
Put your sobriety first, that's what is most important.