You can search by author by putting author: in front of the name you want to search.  So, for example author:"David Bloys" will return a list of all your posts that you've posted with that name. 

The list of results maxes out at 100 results, so you may want to combine other search terms to narrow the results to get exactly what you want, for example you can also search by date.  If you click on the "search messages" link in the forum, there's a link for "advanced search tips" right below the box that shows you how to search by date, by the title of the message, and so forth.