I can’t get motivated.

In my honest opinion, school isn't for everyone. Some people just don't learn well in a classroom setting, and learn better on their own time. And some people, even when being home schooled, simply dislike the work that they are being given. I, for instance, couldn't stand school. I hated it, everything about it. And likewise I couldn't get motivated for the life of me. And I believe this is partially due to the factor of how I looked at schoolwork. I looked at it as something that 'everyone has to do no matter what', and things like that just really don't float well with me. When it comes to society attempting to put rules down, I am the one to go against the current. And that I did. I honestly missed more than half of my school days. And you know what? I regret nothing. I am happy that I carved my own path, and that I continue to do so today.
However during my travels and journeys, I have had the opportunity to see many different things from many different perspectives. And one thing that I learned was that, if you make work feel like work, then you won't want to do it. At least that is how it is for me. Perhaps you feel similarly to this?
In order for such tasks that feel like something that is the last thing we would want to do on our list to seem much less atrocious, I've discovered a simple change of perspective can alter the experience drastically. In other words; if you observe and view this school work as something that you would actually favor and do on your own free time, or as something that you would be interested in learning, then it doesn't feel like such a drag anymore. Because now it feels like you are doing something for your benefit rather than simply another chore that stands in the way of you and the things you want to do.
While changing your perspective may not be as easy as blinking your eyes and then magically feeling differently, it is worth the practice to learn how to do it. It is a great way to turn stressful situations into situations that no longer bother you. Practice this technique, and I believe you will thank yourself in the long run for it.

I can totally relate to this, there are times when I feel completely demotivated and unable to do all the academic work I need to do. What I have done, and this works for me, is come up with a time table for myself, and not a hard one to do at that.Simply after lunch, one hour of work, and one hour of rest. And this could be tweaked to your preference but the aim is to get at least 3-5 hours of work in. I know it's not going to motivate you, but it'll help get work done, and once you start to see results, "Hey, I've accomplished things" it'll be the driving force to continue.There are always going to be boring and tedious tasks in your academic life, but try your best to tell yourself, it has to be done.Also, rewarding yourself after you've accomplished assignments or a lot of work in general helps, be it going to see a movie or a get together. Usually that helps me persevere and carry on with what I'm doing!Hope it helps!

Getting motivation isn't the same for everyone. For school, it is not a perfect system, far from it actually. I wouldn't suggest basing your self confidence and respect based off your success in school. I would suggest finding some other mode of getting motivation to transfer to your schoolwork. I don't know you personally, so you will have to figure out what sparks your motivation. If you say its nothing, then you have given up a bit too fast. Good luck!