Try not to think about symptoms as being positive or negative. When I had my loss (blighted ovum), I was throwing up and feeling pregnant, and my belly was growing. Sac grows....baby doesn't.
I can totally relate to the morning sickness easing up though. I had a bad week of it from week 6-7, and then it sort of just got better. I had my u/s at 7 weeks and 1 day and baby was fine and had a heartbeat. Since then, I haven't thrown up once, but the nausea is still there occasionally, just not as bad. I find I still feel a little icky around dinner time, and I feel sick if I'm hungry.
I've been worried too, but at the same time, a lot of women have symptoms even when in the process of miscarrying. Just try to get excited for your ultrasound. I'm sure everything is just fine.
Maybe your body's going easy on you for a few days and it'll hit you again?