I'm in high school too and we have the same exact problem. Recently I have managed to stand up back on my feet again and developed a decent work ethic out of my low conscious state and weak will power. It's funny since my vision was quite vague. It's like I didn't barely had a vision at all.
This semester I started with a vision and it was to get all my homework on time as I've never (literally) hand in a non over due assignments.
But I also had a feeling that vision is not going to be enough. I had to come up with a strategy. 1. Find your weakness. My weakness was some sort of fear which is largely caused by being disorganized. 2. Develop a strategy. I had to install an extension called Todoist in chrome to keep me on track.
Your weakness is likely fear as well. I'm betting you can't even imagine yourself sitting for 45 minutes studying.
Here's a strategy that I use:
This works every time. Just come up with what's easy and comfortable for you. Let's go with 5 minutes or even 3 minutes. Grab a timer, and study for 3 minutes straight. Then you take 10-20 minute break, make sure you run your timer for this too. Then you set your timer to 3 minutes again, then study. Then you set your timer to perhaps 12 minutes, go grab a drink, meditate, whatever. And Repeat.
Once you feel comfortable and you become eager you can move up to 5 minutes to 10 minutes -- 25 minutes -- 40 minutes and so on. On the other hand, if you dont feel comfortable with three minutes, just go with 1 minute or even 30 seconds (trust me it makes a huge different). If you can't do 30 sec just open your textbook and notebook. If you can't do that just have them sitting on your desk. If that's too hard just sit down and visualize yourself doing it.
The beginning is the hardest part of course. But once you get the momentum then your problem would be fixed.
This strategy works every time, if it doesn't then your probably way way too low conscious in which you need some good sleep, proper diet, and meditation.
