...I dont get it...

So, my scale's battery was dead all last week after my Midwife appointment. No biggie. Jim brought one home yesterday because my Midwife is due to call me today for my 'weigh in check.' I didnt feel that I had gained weight, although I try to eat so much crap its ridiculous. I'm drinking the weight gaining Ensure just to give you an example and I even ate a ton of swiss rolls in hopes it would help! (lets just say there was a lot of tooth brushing going on this past week. haha) I was hoping I had gained the one pound she wanted though. NO. Stepped on it today and I am actually DOWN two more pounds. WTF do I do? I'm so upset. I dont know what is going on. I feel better, I'm taking my iron and prenatals all regularly again now that I'm off my antibiotics, my teeth are actually cooperating. WTF? I'VE BEEN ON WEIGHT GAINERS! Who says that they are 16 lbs UNDER what they originally got pregnant at when they are SIX MONTHS along? =( I've never had this happen before. I just never gained weight til the end with the other two. Any ideas on what I can do? I'm desperate here....