New password - Username in Use?

Hey Moderator help please! I’ve forgotten my old password for this site, because I haven’t posted in ages - Long story, now really need some advice/chance to chat about diet for my PPMS - so requested to set a new password, and change my email address, and it tells me my username is already taken! Of course it is = by me! What gives? Any advice on how to reset my password but keep my original username much appreciated! Thanks, J xxx