I will say that I started my hormones without a doctors care. My doctor wouldn't prescribe them because she didn't know anything about it (trans stuff) and wasn't comfortable with it. It took me some time to find a doctor who knew what he was doing, and would prescribe hormones. In that time, I started my own regiment, which turned out to be basically the same as what I was doing. I was taking Provera and he switched me to Prometrium, which I like more.
Be careful. Even if you can't find a doctor who won't prescribe them, try and to get your blood drawn at least every 6 months. Also, don't over do it. Do not take a ton of estrogen to try and expedite the process, it's not worth it.
There are places that you can get legitimate hormones online. I won't mention them here, but if you poke around on the internet you can find them easily. While I can't recommend this route (and I do not), if it is your only option, then so be it. Just be sane, safe, and reasonable with the dosages.