ignore the people that ask about how you're writing up is going...
concentrate on getting all your lab work done, and 4 months is plenty of time, to accomplish alot! and you wont fail. you can do it! we're all right behind ya!
and there are always more experiments you can do, but you finally have to draw a line. and can always put in the thesis, for future...so do your best and get as much lab work done as you can. and if you're not feeling too tired, try to spend a day or so a week, writing up what you have done, and reading a paper. it does add up!
i've read a thesis that passed, where the student said stuff like, experiment needs to be repeated to verify findings, etc etc. and he passed!