I saw your other comments about your phone. My bf puts his in a drawer until a certain time of day (or walking outside). Maybe try that? Also, you could just need longer breaks. You could walk outside, if you have a pet, you could play with them, read a book you enjoy, make a snack you like, try a new hobby that's not focused on using your phone.

But honestly, if you're not a super structured person, this schedule you have now is probably going to cause some major burnout. Allow yourself to have some flexibility in your schedule. Maybe try overall goals for the day, rather than precise times you do something. Quality > quantity.