YouTube Signed Out

I opened the app today only to find that I had been automatically logged out due to this feature to access YouTube as signed out as opposed to on my account. I cant get back onto my account and its been frustrating me for hours. I for one cant understand what the point of this feature is. Why would I want to go onto this app as anything other than my account that has all of my preferences, subscriptions, and activity on it? Seems to be just another in a long line of bad design decisions.

ARod44 about YouTube - Watch, Upload and Share Videos, v12.32