Asalaam alaikum (peace be upon you) sister Holly.
First of all, you don't
have to tell your family that you've become Muslim. That isn't a problem. So if you think there will be harm in you telling your family that you're Muslim - then you can stay quiet about it.
If you think they won't let you wear hijaab, you can try to do the lesser harm by wearing a bandanna whenever you go out. Since bandanna's cover the hair, and you can wear more covering and looser clothing. Until you feel you can move from this kind of environment, then you can try to wear proper Islamic dress. That's what i've read on some sites when people are gradually working on wearing the hijaab.
We will pray that Allah eases everything for you, and you have a Muslim community who cares for you and supports you soon, ameen. Remember that after hardship, Allah does grant ease, so keep asking Him for goodness, in this life and the one to come. ameen.
Remember that the believer is strong, because they have their trust in their Lord - the One who controls the hearts of all the people.
I want you to read this story of some of the companions of the Prophet (peace be upon him):
http://www.islamicboard.com/companio...i-waqqaas.html
See how he faced this, and learn from their lives so that you can become a stronger Muslimah insha Allah. :)