Time Management

I have trouble managing my to-do list…I have so much I want to get done and feel I have to get everything done because I believe that’s what successful people must do. It doesn’t all fit in my calendar…work supersedes all. Then I beat myself up when I cannot get it all done. I keep re-doing my to-do list again and again, things get moved to different days, and overall I get frustrated.
Would love your input/suggestions!
Thank you!