No, God isn't like this. God loves you, and more than anything He wants to come into your life and welcome you into His family. And He has done everything possible to make this a reality.
Does this mean God isn't concerned when we do wrong? No, of course not. God is pure and holy, and when we do wrong, we are guilty of rejecting Him and going our own way. But He doesn't stand on the sidelines (so to speak), yelling and telling us that if we don't do better He won't love us. He loves us anyway -- simply because love is part of His character. The Bible says, "How great is the love the Father has lavished on us, that we should be called children of God!" (1 John 3:1).
How do I know God loves us? I know it because He sent His only Son into the world to die for us. You see, no matter how hard we try, we can never measure up to God's standard -- which is perfection. But on the cross Jesus -- who was perfect -- willingly took upon Himself our sins and our guilt. Accept the gift of God's love by inviting Christ to come into your life today.
As a footnote, I hope your letter will help some parents realize the importance of expressing love to their children. Your father loves you; if he didn't, he wouldn't care how you did. Ask God to help you express love to him -- and in time, perhaps he'll learn to do the same to you.