Watch little kids at a playground. They never check what time it is.

Full absorption in an activity is the natural state, and it gets trained out of you. Children do not check the time because nothing else is scheduled in their heads, so the game gets all of them, which is why an hour of it can feel like a day. Adults keep one eye on the clock permanently and then wonder where the years went.

Do one thing this week with no time limit attached. Leave the phone away from where you are, avoid deciding in advance when it ends, and let it finish when it finishes.