The way the search works is that it will center on your city, but your activities may be outside the range of the map. You can drag the map to where you know you've started your activities and then click search again.
Help. Me too. I have all of my activities listed as public. I have been able to view all of my activities in the past and only in the last week or so they are not showing up. I haven't changed any settings. They are all under my dashboard. I filtered the search locally, by "my activities", and putting in by username and each one fails.