If the Earnest Money Contract that was used for the 'resale' of your home to this prospective buyer is TREC Form 20-6 (One to Four Family Residential Contract - Resale), look at Paragraphs 15, 16, and 17, to inform you of your legal rights should the BUYER default in his obligations under the contract.
Under Paragraph 15, you may either sue for specific performance of the contract, which, quite frankly, will tie up your property for a very long time, or simply keep the Buyer's earnest money as liquidated damages.
Under Paragraph 16, you may have agreed to arbitrate the dispute, which will also slow the resale of your property and your acquisition of your new lake home!
The good news is that, under Paragraph 17, IF you do decide to sue for specific performance (going through with the purchase) you will be entitled to reasonable attorney's fees, should you prevail!
Ordinarily, I would advise you to take the forfeited earnest money and see about getting your present home resold, as soon as possible!
Sad and unfortunate, but likely the easiest way to resolve your problem.
Eric The(GrainOfSalt)Hun