I am sorry to hear of your problem, and I hope I can offer you some advice and guidance. Ancedotally, there are reports that a diminished sex drive is a rare side effect of endometrial ablation. However, on medical web sites, there is no mention of this. And, on the one site I did find that discussed this, they said it was a rare side effect.
Knowing the anatomy and pathophysiology as I do, I dont see how an ablation could affect sex drive, other than psychologically. The uterus does not make or produce hormones; it is the ovaries and the brain which make the estrogens, the FSH and the LH that are the female hormones. Burning off the topmost layer of the uterus should therefore have no effect on hormones, as it is not the uterus which provides any direction or feedback for the production of those hormones.
But ancedotally it is reported, so it obviously does happen though the mechanism is unclear. It could as well be a sign of premenopause. Certainly around this time, if you are in this phase, levels of your hormones are starting to change, and a change in FSH and LH certainly can affect sex drive as they affect estrogen. You can get a blood test for this to assess if this is the case.
If you find yourself less lubricated, that could be a sign of decreasing hormone levels.
If you are concerned, I would suggest discussing this with the GYN who did the proceedure. The site I will link you to states this should definately be reported as it is a less common side effect.
I hope I was able to help,
http://ezinearticles.com/?Dont-Fool-With-Mother-Nature---Part-II&id=145246 (the article which discussed low sex drive after an ablation)