Had 2 blood panels done 45 days apart. My calcium went from 9.0 - 10.1. Started 2000iu of vitamin D recently. Could that be the cause? Should I worry?

No concern usually. It's possible that the Vitamin D may have caused the elevation, particularly if you had significant vitamin D deficiency. 2000 units of Vitamin D is a relatively small dose and should not cause hypercalcemia (unless you had a co-existing primary hyperparathyroidism in which case hypercalcemia could develop with vitamin D repletion).