When someone gets angry at us, our natural tendency is to get angry at them in return -- especially if we don't think we were at fault. We don't like to be accused of being wrong, and the angrier we get at someone, the harder it is to forgive them.
But God isn't like this! No matter how badly we treat Him, He still loves us, and He still wants to forgive us and become our friend. If He weren't like this, we'd never have any hope of forgiveness or eternal life. But He isn't put off by our anger, nor does He turn away from us if we repent and turn to Him in faith.
How do I know God is like this? I know it first of all because of His promises. From one end of the Bible to the other, God repeatedly promises to forgive all who come to Him in repentance and faith. The Bible says, "The Lord is gracious and compassionate, slow to anger and rich in love" (Psalm 145:8).
But I know it especially because Jesus Christ came down from Heaven to give His life for us. He did this for one reason: so our sins could be forgiven and we could go to be with Him forever. He loves you that much! Don't carry this burden any longer, but ask Christ to come into your life and cleanse you of all your sins -- and He will.