There seems to be a problem with the search facility, but I don't think that the two problems are related.
If you click on your name and view all posts, that is the best way to find posts by you.
What has disappeared? Responses to threads? Is the rest of the thread there - provide a link. or did you start new threads?
You also have a problem making a donation, so I am wondering if there is a problem with your pc?
Brendan