Transitioning from formula to milk?

My main ? is transitioning to milk. My pedi. said I can just give her milk or transition like 1/2 and 1/2. She still won't use a sippy cup even though we try many times a day. She loves a regular cup though. My pedi. said not to put the milk in the bottle, but I know I did with my other dd and I have friends who do it. Is it really a big deal? I am afraid to change to milk because she doesn't eat much food and she won't get the nutrition she needs but my dr. said she will eat when she is hungry. She told me to drop 2 of her 4 bottles and offer her milk in a cup and eventually drop all bottles. What ways worked best for some of you. Now I am going to stress about this. I had so much stress and worry about her development and now look what she is doing. In a few weeks or month she will be drinking out of a cup and I would have worried for no reason.anyway, I would love some advice on how you all did the formula to milk. I thanks Debbie