7 months since I begin my PhD, I haven't yet figured out what I'll do for my PhD project.
No thorough literature review has been done...and all "easier" and interesting projects have been taken up by other lab members (and of course, competitors).
If I could start again, I'd rather take a year off to think about what I really want to do for my PhD.....
it's too late to say this now.

of course not. but you have to think if you are really up for the task of a phd.are u? if you are then carry on the hard work and you will find a something

I know how you feel. I'm 3 months in and up until last week only had a very vague idea of what I MIGHT do. Thankfully though, I've now got an idea to run with. Maybe talk with your supervisor? Tell them what you're thinking might be good, and see if they can help out??

Start losing interest in doing research.
I don't feel excited or motivated to think about science...
All I want now is to finish the damn 3-year PhD!