Someone please help? Is this a miscarriage?

Ok so my periods are very irregular. I usually bleed every 8 days for about 4 days. Iv been off the depo 6 months now

And I know it can take 18 months to be out the system. I did 2 pregnancy tests Sunday just gone and they were both what looks like positive straight away. Picture shown here, the picture doesn’t really do it any justice...

I started bleeding yesterday, which on my calendar.. should be a period. Iv had very sore boobs since Sunday which I usually get before my period.

BUT... Iv done another pregnancy test today and it looks the same as the pregnancy test I did Sunday with the faintest of lines.

What is going on??? I’m pretty scared.

Any advice?

Thank you!!