How can I motivate myself to do things, so that I can feel like my life is meaningful?

Look for people, characters that you admire, or at least think oh it would be nice to be like that person, or I wish I was a little bit more like that person. Then you can start seeing what that person does, and you might like a little bit more of what you do day by day. Another one is to look within, think about the things you dream, or once dreamed of... does it still seem like a nice dream to you? if it is, what should you be doing to start accomplishing it? Many times, many days we don't feel like doing anything, and from time to time it's ok; we are not machines, we need to take a breath, so do, then start again/continue while not beating yourself about taking some breaks

Motivating yourself can start with setting achievable goals. Think of goals in your life that you want to achieve. Some daily goals, weekly goals, and overall goals that you'd like to achieve. Keeping goals organized and written out can help you achieve these goals. Continuously review your goals and the progress being achieved, this can aid in the motivation aspect. Reach out to mentors that can aid in motivating you as well. Breaking tasks into smaller steps can help these goals feel more achievable as well. Lastly, be kind to yourself and understand that life may get in the way at times.