Mindset. Sometimes when you're close to a goal, you simply just tilt. Once you lose a game or two, stop playing, take a short break, and come back will a fresh and cleared mind.
Or simply forget about rating. Try to ignore you're rating and if you lose, you analyze the game and keep going.
If you're actually 1200 strength, you will get there soon.
Three times now I've gotten to 1190 odd, been one game away from getting to 1200 and all of a sudden I tilt.
What is going on!? Why does this happen every time I reach a milestone like this?