There are too many thoughts in my mind, so let go of unimportant things first. When there is nothing in my mind, my thoughts will become clear. I don't want to take a nap at all. Maybe it will be better to get up. The ultimate method is meditation. If you have time and patience, you can try that, which will be more useful. Generally speaking, you can find a comfortable sitting position or lie flat and relax from head to toe. Relax deeply every time you exhale, and pay attention to breathing at the same time. With each slow breath, count a number silently until you count from the beginning to ten, and then count backwards from ten. This will clear your mind of distractions and achieve a calming effect between repeated breaths. Good luck.