I've been having quite a lot of problems with doubt and worry lately. The other night I was in quite a doubt-filled, depressed mood, and I think I slipped into a period of not believing in Christ. Whether it was a minute, an hour, or five hours, I do not know for I soon slept. I truly believe that I entered this period of unbelief for less than an hour until I fell asleep. When I woke up, I knew I was so very wrong about those thoughts. My question is this: I was baptized because I believed and needed the remission of sins. Because I did not believe for a short period of time, do I need to be baptized again, or do I just need to pray and ask forgiveness? I hope I'm not bugging you, but thank you for your time.
Periods of doubt come to even the strongest Christian. Look at the apostle Peter: He doubted when the Lord invited him to walk on the water (Matthew 14:29-31). He even denied knowing Jesus three times (Matthew 26:31-35, 74-75). In each case, he recovered and became stronger. What you don't see is anyone needing to be baptized again when they stumble after becoming a Christian.
The reason is that baptism serves several purposes. Yes, it washes away sins (Acts 22:16) as you start a new life serving God (Romans 6:3-7), but the core of baptism is that you entered into a covenant with God. In this sense, baptism serves a purpose similar to what circumcision did in the Old Testament. "In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ, buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead. And you, being dead in your trespasses and the uncircumcision of your flesh, He has made alive together with Him, having forgiven you all trespasses" (Colossians 2:11-13).
Covenants are lifetime promises. A Jew did not have to get circumcised again each time he violated his covenant. A husband doesn't have to remarry his wife if he commits adultery. A person's sin does not nullify the covenant made. It continues to exist. Getting baptized multiple times doesn't make you any more a part of the covenant than you were the first time you entered the water.
What God has done is give the Christian a way to recover from sins committed after he has entered into the covenant. "If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:8-9).
Therein lies the mistake you are making. You are expecting perfection from yourself, in this case, perfect belief, but none of us are perfect. We all make mistakes -- not constantly, but often enough that we realize that we continue to need God's help as long as we are in this world. To think we can be perfect is actually a sin because we are then denying what God has said. "If we say that we have not sinned, we make Him a liar, and His word is not in us" (I John 1:10).
Christians don't give in to sin; we fight it, but in that fight, we sometimes get wounded. "My little children, these things I write to you, so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous" (I John 2:1). So take the offer Jesus gives, ask for forgiveness, and then move on from there working on your faith.