Exercise is really important for not just your body, but for your mental health and overall wellbeing too!
Sometimes, when we want to move least is when we need it most. Exercise does not have to be hours in the gym every week - you could go for a run or a walk in the fresh air, in a local green space. Once you actually get up and do it, you will feel so much fresher and clearer in your thinking.
Regular exercise has been proven to increase the sharpness of your thinking, and improve focus, as well as motivation. So find something you enjoy doing, and make regular time every week to get moving!