1) Try to change your password using the email you signed in with
2) Ask family members if they did anything
3) Wait a few days, may be a bug
4) Make sure to write your passwords exactly, basically just keep trying. You may have made a silly mistake
5) Try logging in with your email as your username because if you bought a minecraft account and also created a mojang account you are supposed to sign in with your email. If you bought your minecraft account way back like in alpha/beta you should be using your mc name as username.
Maybe try migrating your account to a mojang one if you haven't: https://account.mojang.com/migrate
Enter in your most recent ign/password and enter your email. Then try to change your password aswell.
I don't know what else to say
If nothing works try using a different computer or delete everything minecraft (except your worlds and resource packs) then try to re-install everything.
Good luck!
2) Ask family members if they did anything
3) Wait a few days, may be a bug
4) Make sure to write your passwords exactly, basically just keep trying. You may have made a silly mistake
5) Try logging in with your email as your username because if you bought a minecraft account and also created a mojang account you are supposed to sign in with your email. If you bought your minecraft account way back like in alpha/beta you should be using your mc name as username.
Maybe try migrating your account to a mojang one if you haven't: https://account.mojang.com/migrate
Enter in your most recent ign/password and enter your email. Then try to change your password aswell.
I don't know what else to say
If nothing works try using a different computer or delete everything minecraft (except your worlds and resource packs) then try to re-install everything.
Good luck!