I've often heard that Christians aren't meant to worry. It doesn't always help. Sometimes I worry about the fact that I'm worrying and then worrying about .... I guess you get the idea.
The Lord's Prayer is there to help us deal with our worries. We have a Father in heaven who cares for us. We can seek first his kingdom and ask him to care about our daily needs. The Lord's Prayer is a discipline to help us to trust.
Specifically, Jesus tells us not to worry about food and drink. We need them, but there's more to life than food and drink. And don't worry about clothes. It's the you inside the clothes who really matters.
The Lord's Prayer is there to help us sort out our priorities. Father first. Kingdom second. Our needs third. All important, but in that order.
Do you see why Jesus told us to go away on our own and talk to our Father in heaven? It's to help us get the priorities in the right order. We need time away from the busyness to sort it out.