Does faith mean that you'll never ever doubt something?
I've been sad lately because there are things in the Bible that I don't understand and these things have caused me to doubt Jesus. But when I doubted, I get sad because I think, "I'm not saved because I'm not believing in Jesus." But then my boyfriend told me "If you didn't believe, you just wouldn't care. But if you think you're not saved because you don't believe in Jesus, you believe!"
I can't make sense of my thoughts. It's really confusing. Simple things can become a big deal in my head because of my depression, and big things could not mean anything to me.
Does the fact that I doubted Jesus at some point mean that I never believed and therefore I'm not saved?
It has troubled me too much already. I needed to ask someone who understands the Bible more than me. I can't find anyone better than a preacher. So, what does it mean?
You are making a number of mistakes.
You think of faith as a feeling. It isn't; it is trusting someone or something. I have faith that the sun will rise tomorrow, barring the Lord's return. It isn't a feeling that makes me think the sun will come up. It is a decision that I make base on the evidence that I've seen that allows me to act as if it will happen even though it hasn't yet. When the Bible says, "But without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him" (Hebrews 11:6), it is not talking about having a feeling that God exists or a feeling that God rewards the faithful. It is a decision that you make that you trust that God exists based on the evidence that you have seen. Because of that trust, you then act as if God is present even though you do not at this moment see Him. Faith is what allows a Christian to pray to God, whom they have never met, about problems they have and expect God to answer -- to the point that they live their life as if God has already answered their prayer. Faith is why Christians look forward to a home in heaven. It is a decision to put their trust in God.
You also act as if faith is an on or off quality. God teaches us that there are degrees of faith. "We are bound to thank God always for you, brethren, as it is fitting, because your faith grows exceedingly, and the love of every one of you all abounds toward each other" (II Thessalonians 1:3). Faith grows. When I have faith in something, it doesn't mean I necessarily have faith in all aspects. I might trust my boss to give me my next paycheck, but I might not trust him to keep me employed until I retire. When Peter got out of the boat to walk to Jesus, he had faith ... for a while. "And Peter answered Him and said, "Lord, if it is You, command me to come to You on the water." So He said, "Come." And when Peter had come down out of the boat, he walked on the water to go to Jesus. But when he saw that the wind was boisterous, he was afraid; and beginning to sink he cried out, saying, "Lord, save me!" And immediately Jesus stretched out His hand and caught him, and said to him, 'O you of little faith, why did you doubt?'" (Mark 14:31). Notice that Jesus did not say Peter had no faith; he only said that Peter's faith was small. Peter doubted, but it didn't mean he lost his faith completely. After all, Peter had enough faith to step out of the boat -- the other disciples did not do that much. But Peter let the violence of the storm cause him to doubt that he could continue to do what he was doing.
Your feelings will come and go, but your decisions can remain firm. And there will be times when you aren't sure, that you have some doubts, but it doesn't mean you doubt everything.
Now, one other point. Do you doubt that 2+2=4? Do you decide it can't be true because you don't understand calculus? Then why would you say you doubt Jesus because there is some point you haven't figured out yet? Christianity is about growth. This is why Peter warned: "Therefore, beloved, looking forward to these things, be diligent to be found by Him in peace, without spot and blameless; and consider that the longsuffering of our Lord is salvation -- as also our beloved brother Paul, according to the wisdom given to him, has written to you, as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which untaught and unstable people twist to their own destruction, as they do also the rest of the Scriptures. You therefore, beloved, since you know this beforehand, beware lest you also fall from your own steadfastness, being led away with the error of the wicked; but grow in the grace and knowledge of our Lord and Savior Jesus Christ. To Him be the glory both now and forever. Amen" (II Peter 3:14-18). Sure there are things which are hard to understand but don't let difficulty drive you away from the Lord. Instead, work to become more knowledgeable.