I suspect most believers have doubts from time to time, or at least they wrestle in their hearts with things they don't understand. We might wonder, for example, why God didn't answer our prayers exactly the way we thought He should–and if we aren't careful, this might make us doubt if He really loves us.
But God doesn't want us to be overwhelmed with doubt! Instead, He wants us to be filled with faith–and we can be if we focus on Christ. Do you remember when Jesus' disciples were alone in a boat, and Jesus came walking toward them on the water? Immediately, Peter stepped out and started walking toward Jesus. The Bible says that as long as his eyes were on Jesus, he was able to continue–"But when he saw the wind, he was afraid and, beginning to sink, cried out, 'Lord, save me!'" (Matthew 14:30).
The point is this: Doubts flee when we focus on Christ. But when we become distracted and focus on other things, doubts will begin to grow. The Bible says, "Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee" (Isaiah 26:3, KJV).
Make sure you are committed to Jesus Christ and have given your life to Him. Then make it your goal to grow closer to Him by reading His Word, the Bible, and praying, and having fellowship with other believers every day. When you do, your faith will grow and your doubts will flee.