ectopic vs viable pregnancy

So I went in today for an ultrasound and we are not sure how far along I'm. On the ultrasound they saw a cyst on my left side of my ovary and a possible sac in my uterus. They said I might have an ectopic pregnancy!! I'm freaking out! I first thought I was 6 weeks pregnant so that's what I told them. After the visit today and talking to my husband we now think I might be 4 weeks pregnant. Couldn't that just be a cyst and hopefully the sac in my uterus is a viable preganncy. They Couldn't tell so I had blood today and I have to go back in 3 days for another blood test . Anyone have this happen to them?