I have a very hard time believing that God loves me. I think the reason is because I never had a kind or loving father, so I can't imagine God is kind or loving either. My father was very abusive before he finally abandoned us. — J.McC.
You may be right about why you feel this way about God. I'm not a psychologist, of course, but I suspect many people do what you have done; they transfer the feelings they have toward their parents over to God.
For example, if a person thinks his or her parents didn't love them, then they may decide God doesn't love them either. They may even be angry at God—just as they are angry at an abusive parent. Or they may think they are at fault, and God doesn't love them because they are bad or unlovable—which (they think) was why they were abused or rejected. Incidentally, this is one reason why parents should surround their children with love, instead of constant criticism or harsh discipline.
But listen, these feelings are not true! Parents are imperfect—but God is not. Parents may fail us—but God does not. Parents may not love us as they should—but God does. To put it another way, your emotions may be understandable—but they are deceiving you.
How do we know God loves us? We know it because Jesus Christ was willing to leave heaven's glory and die on the cross for us. The Bible says, "This is how we know what love is: Jesus Christ laid down his life for us" (1 John 3:16). Ask Him to come into your heart today, and then thank Him every day for His amazing love for you.