An agent doesn't book you work. They don't even get you work. They get you AUDITIONS. They provide you with an opportunity for you to book work. It's on YOU.
So how do you do it? Your audition.
You can't control if you get it or not. What you can control is you.
Make a list of what you can control right now.
Make a list of what you like about your Acting. Now make a list of what you don't like and/or would like to improve on.
What can you do to make those better? Who do you need to work with? How long will this take? What do you need to make all of this to happen?
Your Agent doesn't automatically make booking jobs easier. You also need to find an Agent you like and that you work well with.
The same goes with unions. Joining one doesn't equal your value or talent as an Actor. (Repeat that last line over and over until you know it and believe it.)
The bottom line is you have to STOP depending on outside factors and people to validate who you are and think they'll make things easier. Once you realize that and accpet it, you'll be a much happier person and Actor.