I signed a contract and 1000 ernest money but I later changed mind. I want to if I can be sued more than my downpayment
No one here knows the terms of your contract, or what the contract is even about, and you chose to not provide any information. Read your contract. Does it have a limit on damages? If not, you probably have your answer.
What does your contract say and what is it for? Until you tell us that no one can possibly answer you.