What works so far is:
This is what leaves me behind the target and invisible, with the message "Out of range"
I don't know why, but I didn't think you added the '/cast" for the actual attack. I'll try it.
I'm not a rogue, but in general, you need /cast for abilities. If a prior spell triggers the global cooldown, you can't use another /cast after it. To cast another spell after the global cooldown is triggered, you must use a castsequence, and do another keypress. Also note, if the first spell has a timeout value (doesn't look like the case here), multiple /cast statements will cause the macro to stop at the spell that is not ready.