Serum levels of 1,25-dihyroxyvitamin D have little or no relationship to vitamin D stores. They are regulated primarily by parathyroid hormone levels, which in turn are regulated by calcium and/or vitamin D and most dramatically by the injection of PTH.
Your test results may be influenced by the timing of your tymlos injections in relation to the testing.

In vitamin D deficiency, 1,25-dihydroxyvitamin D levels go up, not down.
Just to confuse the situation.