*nods* Ok, I think I understand a little better now. What your parents are doing is the same thing that my friends are doing, and quite possibly everyone here on the board has had someone do to them as well.
Your parents are scared, they are scared of what this in the end means for you, for them, and so on. They are scared that you won't be able to get a job, to support yourself, to find someone who will love you. Everything a parent worries about and the trans bit makes all those fears and nightmares worse. It sucks, but that is just how parents think. Now that may not be all of it, but i'm willing to bet it most certainly has something to do with it. I'm also willing to bet that they didn't quite believe about you until you actually started the HRT and then it got slapped across their faces. It explains their worry and calling up your friends and the lack of personal space.
I think you and your parents are fighting over a miscommunication. I assume since you started HRT you were seeing a therapist, so I suggest you and your parents talk it out where there is a moderator to help keep you and your parent's tempers in check. I'm positive that they will flare while you talk. It sounds like your parents can be understanding if they were accepting up until you started HRT, so I think they will be understanding once things get out in the open.
Hun, I know it seems unfair, but we are all human, and we all sometimes let our emotions and fears get away from us. I don't think your parents have anything but the best of intentions, so just take the time to work with them. I understand you feel lost, but every storm breaks. Even if you have to take a step back, it might be just the thing to see the path forward. So talk it out with your parents and get some outlet for those emotions or they will eat at you until you do something stupid.