Before anything else: God loves you all the time, today and always, and His love never goes away, not even on the days you're sad, not even on the days you're upset.
Have you ever had a day when you couldn't feel God at all? A day when you prayed and it seemed like nobody was listening? That happens to grown-ups too, and it doesn't mean you did something wrong.
Want to know something really cool? There's a story in the Bible about a man named Agur who said something like: I'm worn out, God. Exhausted. God didn't erase that sentence, He left it there forever. Want to know why? So you'd discover you can tell Him the truth, even when the truth is sad.
Now think about a really cloudy day. You look up and can't see the sun anywhere. But did the sun go away? No. It's still there, on the other side of the cloud, the same size and shining just as warm. It's just that a cloud passed in front of it. It's kind of like that with God: some days we can't feel Him, and He's still right there.
And look at the most important thing Agur did: he didn't stop talking. Just a few lines later, he says God is like a shield that protects whoever runs to Him. Whoever keeps talking to God, even on the cloudy day, discovers that.