Do you think it's bad that I've been stealing things from my family and selling everything to a pawn shop?
That sounds really bad, why are you stealing from your family?
I lost my job and they refuse to lend me the money I need to pay my rent. They have so many things they won't miss a few items.
Stealing from your family is wrong and pawning their possessions could get you into a lot of legal trouble if you are caught and your family decides to press charges. You should try to get back the things that you have pawned and return them to your family. If you want to get money, you should work at a job legally.
They'll hardly notice anything is gone. They should lend me the money I need,
It's not your family's responsibility to pay your bills if you've lost your job. As an adult, you need to have an emergency fund to pay for expenses if you experience something like a job loss. Find another job as soon as possible and talk to your landlord to work out a payment plan.