Legal Question in Real Estate Law in Texas

Look at the contract itself; it probably does NOT grant any "grace period." If the law gives you a grace period, the law will also require that the lender put a NOTICE of the grace period in the written instrument itself.

Typically there will be an option period in your contract. If you don't understand it, then please have an attorney review it. Time is not on you side, so you need to do this ASAP.