you need to report this immediately to your bank, social security and the irs. someone has stolen your identity. it will get resolved and you'll eventually get your money but it may be sometime before that occurs. you need to immediately report this. watch your other financial accounts or immediately change the numbers of the accounts (YES< ALLOF THEM) they have your soc. sec. no. and will move quickly to wipe you out.
It takes several months to sort out. Basically you will have to prove that it was not you who cashed the check.