This is why I was such a procrastinator about studying for quizzes /tests, reading chapters and writing papers. At the time it was difficult for me to sit down for more than five minutes and read or study unless what I was reading was very very interesting to me then I could read endlessly and not get bored and become totally immersed in what I was reading but that didn't happen too often. I wish it always happened. It would have helped in college.
Maybe you could set aside a part of the evening for studying and think to yourself you will not stop studying until you reached a preset goal. That way your mind can become aware of what you wish to accomplish. You could get a planner and write down, ahead of time, when you will study, making a written schedule to follow. Maybe after you are finished you can do something you really like, positively reinforcing the study habits.