No, you don't have anything to worry about. Symptoms come and go as they wish and don't mean anything is wrong. My symptoms were few and very scattered, never consecutive days. Don't worry; I'm sure everything is fine :) Congratulations on your pregnancy!
The EXACT same thing happened to me, I had my ultrasound at 6 weeks, strong heartbeat, and EVERY symptom possible for about a month and a half, then everything disappeared around 8 1/2 weeks, it's completely normal, I'm 12 1/2 weeks now and still have no symptoms, we're just blessed with easy pregnancy's I suppose! :]
Be happy you don't feel like poo! I was never sick just had sore bbs and constipation, I am 22 weeks now and still feel good! Be happy :)
Every woman and every pregnancy is different...with that being said, it can be completely normal to not have symptoms or for them to come and go. I was virtually symptom free other than the sore breasts and fatigue until week 8...then week 8-11 I had morning sickness, sore breasts, and fatigue. Week 11 it just about all went away! I have felt fantastic ever since!
Some peoples bodies accept the pregnancy and get used to the hormones much quicker than others. For me I only felt nauseaus (sp?) for the first 2 weeks. After that all my symptoms just disappeared other than being really tired and having headaches. Is this your first pregnancy? If it is, this could just be the way your body reacts to pregnancy. I wouldn't sweat it. Just try to enjoy not having too many symptoms at the time being. Who knows, they could come back in a couple days!