Have you tried the advanced search options page (link
You can add a few restrictions to make it likely that you will find your post. Put in your keywords, put your name in the Filter by Member Name
box and check the Match Exact Name
checkbox, change the Search posts from...
dropdown to 180 days and choose the Newer
radio button, and change the Result Type
option to Show results as posts
. Perform the search, and you should get a listing of posts you have made in the last six months that match the keywords you have specified.
Give it a shot.