But if you think that getting a flatmate that you hardly know will be no better than living in your current arrangement then you may as well continue living in your current arrangement until you are happy that you have a job which is definitely secure and will definitely provide you with MORE than the money you feel will be required to pay off all your potential bills.
Summary: If it's really that bad at home, then you shouldn't be worrying about living with a random stranger in a flat. If you are worried about that, then maybe your family isn't as bad as you say they are.