2015 is GONE so let it go! The past is the past and you can't do anything about it! You can't change it so stop reliving it (if you are -if not than good for you!!)
To stay motivated is to stop looking at the past and perservating on it because it will only waste your time.
Why do you want to waste your time on things you cannot change? Go ahead and think about some of the things from the past but don't live in the past - good or bad memories only take away time from the here and now!
Today's Motivational Monday pic quote is - "Don't let yesterday use up too much of today" by Will Rogers.
Keep saying this today every time you get caught up on thinking about anything in the past!