Also spelled ndeeotteokada, ndeoteokhada, ndeottokhada
so what do I do?
-(으)ㄴ데 states the problem and 어떡하다 — a squeeze of 어떻게 하다 — asks what to do about it: 오늘 밤에 옷이 필요한데 어떡하죠?, 집이랑 직장에서 엄청 먼 곳인데 어떡하지, 지금 8시 반인데 어떡하게. Often it is not a real question but a helpless protest: 근데 단비가 소중한데 어떡해요. 어떡해 is the casual form and 어떡하죠 the polite one; all of these lines are speech, not writing.