Hi Sonia!
It is good to have doubts. It means that you are thinking critically. Someone once told me, before you doubt your beliefs, doubt your doubt. Question to see if your doubts really are what they seem to be they are. And before I go on any further, remember, do not use Science and Religion. Religion cannot solve science, because science is ever-evolving about the mechanics of the universe. Religion is the spiritual side of the universe. It is too difficult at this time to combine the two for mankind. If science says that man came from a fish, then, okay, according to science, we came from a fish, and that is that. You can also say, According to the Bible, we were created in the image of God, then we are children of God.
Religion cannot explain everything in the universe. The prophets from the Bible had very little knowledge of the universe as we know today. And God does not give all the info of the universe because He thinks that we need to learn how to get along with each other before he introduces us to other life on other planets. I mean, we have had people like Hitler and Stalin in the last century, do you think God wants us to commit genocide on an alien race?
Science if very analytical, but it came from very mundane things. It is a good thing, always trying to change how we view the universe, but I should warn you. Do not put so much faith in science because even science states that we should not put so much faith in science, because the purpose of science is to pursue truth about the world around us and the universe we live in. Theories that have been made and defended in science have been classified as untrue or false years later, it is because we find proof to debunk those theories. Right now, the two theories that are confronting religion is the Big Bang Theory and Evolution. So, most of the scientific community support that we came from fish and monkeys. Okay, I get it. Makes sense, right? So, if the Bible were true, why did it say that the Earth was created in 6 days and that we are the image of God? Think about it this way: the prophets of the Old Testament were pretty much savages and cavemen. They cut off the arms of thieves, and kill those who insult them. That is the world they live in. They know nothing of light speed theory, genetic engineering, and helicopters. I mean, look at the pictures in religious texts. The angels have feathered wings, as if a drunk man had relations with a freaking swan! It is what they imagine angels in the air, because they know that birds have wings and they fly in the air, so angels must have wings too, because how else can they fly? Take a lot of religion with a grain of salt. If it sounds foolish, then okay, it may be foolish, but the teachings of Christ, try to live them, ponder them in your heart, and ask yourself, can Science really answer questions of the soul? No, they can't, and they won't, because that is not the purpose of science.
Bottom line, don't mix science and religion. Its better that way. You can believe in Evolution and still be a good Christian if you follow Christ's teachings. And, me being a Christian myself, I want to you tell you, the Earth wasn't created in 6 days. I am not sure how long it took. The 6 days is a symbol. It could mean 6 million years. Or six days in God's timeframe which could be billions or more.