Can someone help me understand how this works? I miscarried 3 weeks ago, I took a pregnancy test 5 days ago and it was negative. I also believe I am pregnant again because I’m having symptoms that I had during my 2 week wait last time. I took another pregnancy test yesterday at 4pm and got a faint positive, I took another one this morning at 5am and it was a little darker. If I had leftover HCG from my last pregnancy, wouldn’t it be the same level or lighter as the first test I took? Could this be a new pregnancy?

The top half of the collage is the test from yesterday, bottom half is from this morning.