Fear of not being saved and cast of to Hell?

i have been told that i am saved countless times yet however i have this engraved fear in my mind, What if? when i take my last breath there is no going back to make things right (if i have done wrong) and there is only forward and no pause.. i fear that when i die i may go to Hell, knowing once a soul gets there it will abound for eternity.. i cant seem to trsut in God for some reaseon.. i really live in Fear and worry wether im saved or not.. it petrifys me to think of hell and its eternal realm..