Pregnancy tests lines getting fainter

I found out I was pregnant December 31st and according to the app I was 4 weeks pregnant today I had spotting not a lot it never went on my underwear wear it was just there when I wiped then went away iv had a little bit of cramping but nothing that has be worried though I did have a pinching feeling on my right side earlier, I took another test just to make sure because the blood scared me and the line is fainter then is was before has anyone had this? Did I just have chemical pregnancy?

Bottom is what I took on the 31st the other 3 are from today

Also from the 31st