So I'm a week late on my period, I took a few tests and at first they were so light could only see with a flash on it. Every day I've been testing for a little over a week now and my lines have been progressing, but digitals still say "no/not pregnant". I'm using all types of brands of pregnancy tests to get better results. So I went to my doctor they took my hcg blood test and it came back at 4. So they say negative pregnancy. This was on Wednesday I went in and got results Thursday. But this morning I took another test and this is the darkest line I've gotten and the pic was taken within the first minute of peeing on it. Has anyone else experiencing anything like this? Did I find out extremely early? Is this a miscarriage? Why are my lines still progressing?

The picture attached is top test: Monday morning middle is from Wednesday afternoon and bottom is from this morning today! These are only 3 tests I have so many more that have same progression lines