I get it, some mornings we wake up and our hair doesn't fall the right way or you have no clothes that you think look "good" but beauty does not stem from our exterior, but rather it starts inside of us. To be beautiful is to be happy. If you want to feel beautiful, try feeling happy first. There is no way you can't feel beautiful when you start your day with a smile.
It's Sunday, the day most consider a day of rest. And that's exactly what you should do for yourself today, rest and relax. Remember that mental health is just as important as physical health, it is hard to have one without the other. You need to have a balance of both in your life. If relaxing to you is still getting in your morning work out, then so be it. But if relaxing to you is skipping the gym and going shopping, soaking up the sun, or spending time with your family or loved ones, then do exactly that. Get lost in a book, go out for brunch, catch up on your favorite TV shows. You cannot feel beautiful if you are sad or stressed. Take time today to do something that brings you joy and let your inner beauty shine through.