For me, a lot of the time when I feel like this it’s due to outside stressors. What I do when I feel like this, or depressed, is I delete Instagram and any other form of social media (this doesn’t count). I start changing my daily routine and limit screen time at home. I read before bed (even though it takes time to learn how to focus on it). I guess it is one of those things that you have to make a choice to overcome everyday. Like people have said, practicing meditation is helpful. For me I found it too challenging, maybe it’s the stigma of it or something. So instead of meditating, I stretch before bed and focus on my breaths and how my body feels. My mind will wander, but it is more about grounding myself than removing all external thoughts.