Have you talked to a doctor about why it is happening physically? I would look into if you have something going on medically. You are very young. Doing kegel exercises might help you control your bladder better.

You can't get restraining orders on people unless they physically attack you (or threaten to, I think).

Your mother blaming you for peeing on purpose is really strange. What's that about? Why does she think such a thing? She knows about your problem because you have no lock on your door you say. Did she walk in on you and discover this happening? There are some serious lack of boundaries there.