Why can't I sign in on Minecraft.net?

I've never changed my password or username and I had no problem signing in a couple days ago?

I covered my name so no one can steal my account

Alright, you need to log into mojang.com and go into settings (Don't know what's its actually called). Once their it says password/email, you can change those and minecraft will email you link to change it (To make sure its you).

If you forgot your email or can't login to mojang you have to email them with your account info.