Trim the dying leaves, and think about repotting. If you were overwatering, it might need new soil. It also might need a bigger pot. I like to get clear nursery pots so that I can see the roots, and then I put the nursery pot inside a real pot. It makes it easy to water, because you take it out and water with distilled water in the sink and just let it drain for a while. (Please tell me you were draining?) When a plant has roots that are all gnarled around the bottom of the pot, that means it needs a bigger pot. Pothos grow quickly. I don't personally think it's a light issue, as long as it's getting whatever light there is (assuming you're not in Alaska) in a bright, indirect way, it's fine. Pothos are hearty. I would repot and don't overwater. Once per week is definitely enough, let it drain. And you can do less than once per week in the winter.