Take care of yourself and your feet, you will burn out way to quickly. Soak your feet after a shift in epson salt and bathe in it too if you can. You need to speak to your manager about this. I did this a few years ago and was scheduled for 28 hour weeks yet stayed late and came in early so much I was getting over 45 hours a week sometimes 12 hour shifts. The over time is amazing but not when you do it consistently and then the team assumes you will always step up and when you don’t drop everything to go in your the bad guy. Talk to your manager about needing more support in your shifts, or at least needing a better heads up when you are going to be needed to stay longer. Don’t let them expect you to always take everyone’s shifts, cuz next thing you know it will no longer be a favor but a regular responsibility

I know its tough, but try to see it from another perspective. I work in a very busy location too and we are all a lot of new baristas, but its important to remember that sometimes its just busy. You can ensure satisfaction the fastest you can, but the regulars and general public prob know your store is always busy. Just take a step back from the stress, take a deep breath, and let autopilot kick in. That’s how i get through my mega long shifts :) good luck!

Make sure to share with customers as needed, they usually empathize esp if you try to have a good attitude throughout the mess. Especially nowadays when people are quitting on a dime, they should appreciate you. Don't be afraid to vent... and say no when you need a day to recoup.