Sorry to hear that. It probably should have been changed a few years ago, but who knows and in any system with multiple moving parts, and bearings spinning more than one thing can go bad. Maybe you could see if you can get another set of ears listening, or get a second opinion. Sometimes you can get a decent alternator at a pick and pull place, that would probably be the cheapest way to throw parts at it. You could also wait a day or two and see if there is any further improvement.