by yourself

by (oneself)

1. Alone. Because there's usually so much going on with the kids, I really enjoy spending a quiet Saturday night by myself.
2. Through one's own efforts alone. You can't move that table all by yourself! Here, let me help you. My little girl loves to get dressed by herself, so tutus and cowboy boots have become the norm around here.
See also: by
Farlex Dictionary of Idioms.

by yourself

 
1. with no one else present; alone. Do you want to sit here by yourself, or can I sit here too? Don't sit at home by yourself. Come to the movie with me.
2. with the help of no one else. Can you really do all this cooking by yourself? Bill, can you lift this box by yourself?
See also: by
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • at will
  • at the end of (one's) fingertips
  • be hoist by (one's) own petard
  • be hoist with (one's) own petard
  • be hoist with one's own petard
  • be hoist/hoisted by/with your own petard
  • be on (one's) pat
  • at (one's) doorstep
  • at doorstep
  • a ball and chain
References in periodicals archive
And they'll all look like they're fairly mature, which will make you feel a lot better about being the 30-something dude drinking beer by yourself.
Think you have to go for your goals all by yourself? You don't!
YEARAHEAD You can't do everything by yourself. Go ahead and depend on the people around you when you need to.