Account Issue

So a couple of days ago I was logged out of my account when I opened the launcher, which doesn't usually happen but I got out and back in then logged in and everything was fine. But then today I tried to get in but for some reason I'm not logged in as DastardlyToast (which is my username) but as the start of my email. When I was logged in with this one, it said I needed to buy Minecraft instead of letting me play, so I tried logging into the account that said DastardlyToast, and I put in my email and my password but then it put me back into the account with the start of my email. I did this a couple of times but the same thing happened, so I deleted Minecraft and reinstalled it, then tried logging in. Now the account with my actual username doesn't even appear and only the one with the start of my email. I tried resetting my password, using codes that are sent to my email instead of a password but nothing's working.

The image is proof that I've already bought the game.