Wish I could help. I don't have any tool to look up users or their many logins. In the time I've been the mod for this forum I have deleted only one post without the permission of the poster. I've deleted fewer than a dozen where members requested their own posts be deleted. So, your post is probably right where you left it.
You could always do a brute force search, simply looking in every thread going back in time until you find it, and your original login. I wish I had better advice for you.
Good luck, and good hunting.
Scott