Pregnant and again after miscarriage?

I am pregnant again after losing my first pregnancy in July. I'm about 5 1/2 weeks but I havent had my first appointment yet. I am so nervous and worry about every little twinge in my stomach. With my last pregnancy I felt great the whole time except for a few waves of nausia, until right before I actually lost it. But with this one Im already having cravings (sweet potatoes) and im queasy all the time and have awful heartburn. I also get tired so easily and usually need a long nap after work. Ive heard this is a good sign because it means your hormone levels are raising and that is what is making you sick. My HCG levels were not raising properly last time and that was the telltale sign I was losing my baby. Is my morning (or morning noon and night) sickness a good sign? Im so nervous I can't take losing another baby and neither can my husband.