@Jeffrey806 so to confirm your situation:
1) On booking you were shown the cancellation policy and went ahead
2) On booking you formed a contract knowing the cancellation policy
3) On booking you believe that renting in Thailand is illegal bet went ahead anyway
4) On booking you knew of your health issues but didn't ask any pertinent questions to the host
5) Now you are scared by a streetscape that is presumably not what you are used to
6) You now want to break your contract and get your money back.
Does this encompass the situation?