Strong positive on pregnancy test

Hi everyone! A little background on me first.. Found out last November we were expecting, everything from the get go just seemed off. I didn't get a positive pregnancy test until 2 weeks after AF was due, baby was slow to grow and ended up finding out we lost him 2 months later when he was still only measuring 7 weeks.

Fast forward to now.. AF isn't due until April 29th. I took this first test yesterday, which showed up immediately, and the second test today. Went to the doctor yesterday who stated i was 3 weeks 5 days.. My question is, why is the pregnancy test so dark? I wasn't getting dark lines last time until i was closer to 6 weeks pregnant?

Sry so long!