Simple poem. In need of opinions.?

I don't see any grammatical mistakes and the commas are where they should be. It's a nice poem and has potential to be even more. It ends so abruptly. It just seems like there should be more. Maybe you could tell us why you feel this way. What does his love do for you that would cause all this pain if it were gone. I just think you could expand the content a bit. Also, You might consider dropping "a drop" from the 5th line. I also agree with neonman in that "once" just doesn't work there. It seems awkward. Nicely done, though.