YouTube changed settings and won't let me log in?

My youtube account stays logged on all the time. today it logged me out and i tried to log back in. it told me to use my whole gmail account, which i dont have one, but i put @gmail anyway, which didnt work either. I know this is because they changed their settings, but i dont know how to log in now. and i know my password, and i have also clicked help adn everything.YouTube changed settings and won't let me log in?See if you can log onto you gmail account.