MeganBeth-
Your stats show that you are currently 10 weeks along-is there a particular reason why you are worrying about a multiple birth? This is something really that won't be able to be known for sure until the midwife or OB hears multiple heartbeats, or it is confirmed on an ultrasound. Were your levels during your bloodwork high or something making you believe that you might be carrying multiples? Don't worry about something until you know it for certain...no need for unecessary worry.
With my first and third pregnancies I had severe morning sickness for about the first 10 weeks or so, and then it started to subside. If you lose a few pounds during that time, I wouldn't worry too much, but if it is excessive (like over 10 pounds, I would just ask my midwife or OB about it. If you are feeling it start to subside, then you are probably doing fine. My worry happens when at 18, 20, 24 weeks etc. that women aren't gaining any weight...and I worry that a weigh in thread might compel women to gain LESS weight because of the comparison factor. (SHE has only gained 8 pounds at 24 weeks, so I am going to aim to gain only 7...that sort of competitive thought process, when now is not the time for it.)
As far as the nausea, I found that it helped me to eat small snacks throughout the day, rather than large meals. When your blood sugar drops, you are more likely to get nausea.