6 weeks pregnant with my second child

I am just 6 weeks pregnant with my second child but I am so worried and stressed as I don't have next to no symptoms. 
I have very sore breast, they are that sore they can not be touched. 
But other than the sore breast I have nothing. I am so worried!!
With my first son I was very sick all the time, every day right up till about 16 weeks. 
I am really wanting to have an ultrasound just to confirm my little Bub is all ok.