My provider has told me I should take 2,000 mg vitamin D3 daily, and I don't have a deficiency.

As for all the advice, the most important thing I can tell you is to let your GP how important you feel this issue is. It sounds like he may not be paying that much attention to it because you don't appear seriously upset. One of those cases where a controlled freak-out may be called for. You need the problem addressed, not blown-off.