One after another

I am really really sorry if I posted in the wrong group. But I really can’t put my mind at ease. First, I felt very very anxious to even test until I am three or four day late as I was so scared of not seeing anything on the test. The test turned out positive then the second thought come up soon after. I have dull pain this and there.. on my pelvic and not a severe pain but I could tell it is pain at my lower back on and off and feel uncomfortable around my lower abdominal area. I am thinking of ectopic. Of course I will go for a scan. But will it be too early to see even a sac now? I would be 3 weeks on 14th.