Right there with ya, OP!
I made space to find myself. Get rid of your ex's stuff, and anything replaceable that reminds you of him. Clean house, physically, and get rid of clutter. It's surprisingly good at helping clear out emotional grunge, too.
Next, try new things. I took tennis classes at the YMCA (bonus: childcare was available!). New things often mean meeting new people, and those people like to do things, so there's another opportunity to go try more things... It's one of those "...how can you know who you are 'til you know what you want..." things (which is totally a quote from a Sondheim musical I took myself to see, and see how handy it can be to go see/do new things!

) Throw a bunch of new activities into your life and see which stick.
Third, but perhaps most important, DO NOT go looking for someone. Seriously. This is the absolute worst idea. If you don't know who you are and what you want, you're a liability to those around you, and that lack of self-knowledge is going to seriously hinder any new relationships you may form. Stick to casual friends/activity buddies for a bit.
Give yourself time, and be gentle with yourself. Don't lay on (additional) guilt by feeling selfish for taking time to find yourself. It's important work. "Walk around feeling like a leaf. Know you could tumble any second. Then decide what to do with your time." (A quote from a poem by Naomi Shihab Nye. I also discovered I like poetry

)