Different symptoms with second baby

I'm 6 weeks and 3 days and I have small symptoms. Fatigue, breast tenderness that comes and goes....mostly at night. Peeing frequently. But other than that no nausea or vomiting. It's hard to believe I'm pregnant with no hard core symptoms. With my first I think I started getting sick around week 8.... not sure. I have a sono scheduled for the 16 of this month so until I see that heart beating it's driving me crazy! The only thing I can really do to reassure myself I'm pregnant is keep taking tests. Am I crazy? Or is this normal?