The big warm welcome to Susan's, Elin, you will find that these forums have many wonderful people here that have a vast amount of experiences. There is a wealth of knowledge available to you and some tremendous resources. Everything is right at your fingertips, so pull up a chair, relax and let your fingers do the walking.
As far as your doctor, is this doctor, a general practitioner or an endocrinologist. An Endo is the one that is best trained to guide you with hormones. They would be able to prescribe the right medication based on your health and any medical conditions you might have. They would also monitor to make sure all your blood levels are not changing to drastically, but the appropriate levels are being maintained to give you the feminization that you are looking for. I really do hope this answers your question. I wish you nothing but the best of luck on your journey and may the Angels always look upon you and guide you on your path.
Hugs,
Melissa Ann