You dont even have to go to a doctor...there are online testing services that will test vit D w/out a prescription. IO checked mine quarterly for several years.
Supposedly it takes almost 60,000 IU a day for a long period of time to cause harmful levels of calcium in your blood. All supplements recommend 1 dose a day and the largest dosage is 10,000 IU. I see little risk in attempting self medication here. I'll consult my doctor at my next routine checkup, but I'm not worried about this.
This isn't something you should self-medicate. It's tremendously simple for a doctor to confirm your hypothesis.