Yes, God understands -- not only how you feel, but why you feel this way. One of the Bible's most encouraging truths is that God knows all about us, and yet He still loves us and sympathizes with our weaknesses. The Bible says, "For he knows how we are formed, he remembers that we are dust" (Psalm 103:14).
But God doesn't want us to stay weak, or cut ourselves off from the help He wants to give us! So far, you've had a rocky road in life (as your letter makes clear). But you know this, and down inside you want to know God -- which is why you've decided to give church a try. I'm sorry you haven't felt comfortable so far, but I strongly urge you not to give up. Ask God to lead you to a church where you will feel comfortable and accepted, and can find the spiritual help you seek.
But you don't have to wait until you discover the "right" church! God loves you just the way you are, and He wants to welcome you into His family right now. Tell Him you know you need Him, and want to leave your old ways and turn your life over to Christ. Jesus' promise is for you: "Whoever comes to me I will never drive away" (John 6:37).
Then tell a Christian friend what you've done, and seek out a church where Christ is preached and followed. Let the pastor know what you've done also; he can introduce you to people who can help and encourage you.