4th year PhD student(24 years old). I am lost
It's a common opportunity/risk of a grad program that you have the cover to spin your wheels.  I blew a quarter once.

A small piece of advice that worked for me.  I enjoyed the childish pleasure of seeing my byline on published articles.  Maybe you can use publishing to motivate you?

My advice is to write up and publish any work that you have/can.  Just literally start a computer file, name it, add the various sections as headers (abstract, intro, etc.).  Then hit save.  You're started now.  Then work on WHATEVER PART IS EASIEST.  Not in order, not in logical progression.  But whatever moves (could be conclusion first).  After all, the darned thing is in a computer...you can always edit it!  This is so much better than the typewriter era.

If you don't have any data, I suggest to write up an outline publication of what you will publish when you get data. You probably know at least enough to do a decent intro section, citing the literature.  I have found that having the paper started can actually motivate the experimentation.