You might try clicking on active topics. You might need to adjust the show topics time to a later date. If you find one message of your you can click on your username and it will come up with a profile page that allows you click a button that takes you to a search page to find your posts. You can also just hit the search button and then do a search by posts using just your username.
Wish there was one simple button that would bring up posts I've started or replied to instead of having to go through some of the those steps though.