I just don't get it?

I had a doctors appointment this morning and I lost 1 kg from my last appointment 2 weeks ago. What really boggles my mind is that I have been eating like a horse, I just seem to constantly hungry.

So at almost 20 weeks my weight gain is only about 6 lbs, I thought I would be in for it this week because of how much I have been eating, but apparently not. Oh well as long as baby is doing well that is all that matters.