You can sue the seller for fraud.  Fraud is the intentional misrepresentation of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you justifiably relied to your detriment.  In other words, you would not have purchased the house had you known the true facts about the extensive mold problem.As to whether or not you should stay in the house, that is a medical question for a doctor.Your damages (the amount of compensation you are seeking in your lawsuit) for fraud would be either the benefit of the bargain or your out of pocket loss.Benefit of the bargain means that a defrauded purchaser can recover the difference between the real and represented value of the property purchased regardless of the fact that your actual loss may have been less.Out of pocket damages for fraudulent misrepresentation  permits recovery of the difference between the price paid and the actual value of the property acquired.