does anyone feel lost when you are writing your thesis?

Do it in small, (very) manageable chunks, and tie them together / move them around later. If you sit there having to sift through 80,000+ words-

It's all about strategy and research management. Have a timetable, precisely timed tasks in it and stick to it. Plan chapters first, rather than starting with nothing. It's all in having the right tools for the job.