Romans 14:17 says, "The Kingdom of God is not a matter of eating and drinking, but of righteousness, peace, and joy in the Holy Spirit."
The Kingdom of God is not made up of temporary things that only last for a moment...like food, or drinks, or candy. That's why Jesus says we don't need to worry about stuff like food and clothing (See Matthew 6:24-33).
We can know that God cares for us and His plan is for our good. If we choose to do what is right : that's thinking God's way, and acting God's way we will have peace and joy.
It doesn't mean that things always go well. Sometimes things are hard, but we can have God's peace and joy when we are in right relationship with Him.
Nehemiah 8:10 says, "The joy of the Lord is your strength."
Where do you get your joy and peace from?
Is it...the joy of my video game is my strength?
or...the joy of watching television is my strength?
or...the joy of playing sports is my strength?
or...the joy of being with my friends is my strength?
or...the joy of having money is my strength?
So many people base all their peace and joy on temporary things, rather than on a long-lasting relationship with Jesus. Hang onto Jesus and you can have peace and joy as part of his kingdom!