Finished a research paper and feel horrible now

I don't have a name for it, or a scientific basis, but I experienced exactly what you are describing: a general numbness/boredom that lasted a couple of weeks after seeing a paper published - everything was pretty hectic up until that point.

My guess is that this is due to something called 'lifestyle changes' (also a hypothesised contributor to postpartum depressions) - your life changes almost instantaneously upon submitting a paper. Before that you were totally hyped up, working really long days, getting by on the fear that things wouldn't work out and the adrenaline when it turned out they would after all. And then when you're done you are exhausted and all your previous drivers (that all related to getting your research project done) are gone. You have to recuperate and you have to find something new to live for (next project? family? a little bit of Mozart maybe?).

Good luck!

Perhaps you could quickly find something else to get involved with, at a more liberal place. The brain is very "hungry" and can cause you to "act out" when it doesn't get what it wants. But some light tasks and a little bit of physical involvement (outdoors, indoors, but not indoors studying) may help.