Exactly how I felt! I'm 31 now myself. I'm really hoping my experience is like yours, because I'm still not 100% myself again. Currently 2.5 weeks in.
I can't even imagine what my levels were prior to taking the 500% RDV supplement I was on before having my blood checked. But at <9ng/ml, I most likely have osteomalacia.
All doctors will only prescribe D2 (ergocalciferol); so you really need to go and get D3 (cholecalciferol). Your body naturally produces D3, and the latter is much more bioavailable. Because of this, you will also want to scale down your dose and not take as much. It's possible to go too far and end up with hypervitaminosis, which ironically can also cause random bone pains, and calcification of your arteries.
It's important to test your 25(OH)-D levels every few months when taking extreme supplements.
Also, be sure you are getting enough calcium and magnesium. These are the chemicals needed to maintain healthy bones. Doctors do not prescribe the magnesium, and large vitamin D supplements will deplete this, also leading to calcification and other problems.
Finally, for anyone living north of South Carolina, you will not receive enough UVB radiation from the sun to produce sufficient levels of vitamin D during the winter months, and milk really has very little vitamin D. So you might want to test and possibly supplement if you are experiencing random musculoskeletal pains. Low levels are fairly common, and usually not a huge deal. But at my level, it was fairly severe.