Fed the fuck up. When you're half way through getting done with exams and can't take it anymore. It can also refer to being extremely bored or even just annoyed at work. People may also use FTFU in reference to someone being annoying or when you can't be bothered doing more chores.
'There's so much to learn. I'm so FTFU!'
"Work is slow today. Im FTFU and just want to go home"