Bug username account

I have a problem since the new update of launcher.

My username is normally Zennobia. Yesterday, all was fine, i had no problem. However, after the new update, i logged in on my server, and my nickname was no longer Zennobia, but "HappyMappy", so I lost all my stuff and links with animals.

When i check on the website of Minecraft, it tells me that i changed my username 15 days ago, but i didn't.

Can someone help me ?