@claire it doesn't really matter what your estrogen levels are. they fluctuate wildly over the course of each day even if you're on injections but especially if you're on oral/sublingual. what's important is to keep your blood pressure and fasting lipid panel at nominal levels, and to be getting the psychological and physical effects you want out of your HRT doses.

this is the canonical best practices guide, if your doc is ever not doing what you need slap them with it: http://transhealth.ucsf.edu/trans?page=guidelines-feminizing-therapy