I am afraid I am going to be wrongfully terminated tomorrow. Can they deny me severence pay if I dont sign the termination documentation?

Do you have a contract, or some representation by your employer (could be in an employee manual) that employees are entitled to severance pay upon termination?  If not I am aware of no requirement that your employer provide you with severance pay.  If the employer does offer to pay you severance pay, it may make such payment conditional upon you signing an agreement releasing any claims you may have against it, or other termination documentation.  You have every right to refuse to sign it, and to pursue any claims you feel you have, but your employer likewise has the right not to pay you severance pay if you do.