✔ 最佳答案
1. Yes. At any times, you can ask to cancel the contract. The only issue if the landlord will say yes and the consequence.
2. Definitely not in your case.
3. Not necessary.
In your case, your security deposit is definitely gone. However, if you can convince the landlord that you have no money to pay anymore (with proof), maybe the landlord will allow you to cancel the contract with any further consequence (as you know, it takes money and time to kick a person out).