Not gaining weight

So, I'm about 8+2 & this is my second. I haven't had an ultrasound yet but I'm scheduled to get one next Tuesday. My question is, has anyone had similar issues as far as weight goes? I haven't gained any. I weigh myself every morning before I eat but there's been no change. With my first I gained a total of 60lbs & lost all but 20 after he was born. So I'm kinda nervous about what's going on...or the lack thereof. Thoughts?