Very dark lines.

I'm in need of some education or explanation. As you can see in the picture, 2 very dark lines. I always see people get faint lines, and so I figured the darker the lines the more pregnant you are.

I tested positive April 27th.

Went to the doctors May 18th. Had a vaginal ultrasound. Found out I was only 4 weeks along.

My last "period" was April 4th-7th.

I just don't get how I got such dark lines being only 1 week pregnant? Could I be farther along? Possibility of multiples? It doesn't run in my family though.