Nowhere does the Bible teach that we will have a second chance to receive Christ and be saved after we die. This is one reason why the Bible says, "I tell you, now is the time of God's favor, now is the day of salvation" (2 Corinthians 6:2). I pray that you will take this warning very seriously.
In fact, the Bible teaches that this life is the only one we'll ever have this side of eternity - and if we're ever going to turn to God and put our trust in Christ, it must be now. In other words, we are not promised a second chance, either through coming back to earth again (which is what those who believe in reincarnation claim), or in some intermediate state after death. The Bible says that "man is destined to die once, and after that to face judgment" (Hebrews 9:27).
I suspect your real problem, however, is that you don't understand what the Bible teaches about salvation. If our salvation depended on how good we were, then you'd be right: We'd never live long enough to cancel out our sins. In fact, we never could do that, because even one sin would keep us out of heaven.
But Jesus Christ came for one reason: to make it possible for us to be saved. He did this by taking all our sins upon Himself, and suffering the judgment and Hell we deserve. Think of it: All your sins were placed on Christ, and He died in your place! Turn to Him and confess your sins to Him today, and then ask Him to cleanse you and come into your life and save you - and He will.