What does this mean?

So this morning I've done 4 pregnancy tests, the first one was positive

I then took these straight after

I went to the shop and got a first response and i can't see anything,

this is using the same fmu. I am due to start af today and I am having some bleeding but I also had a smear test yesterday.

I am so upset. I thought this was it.

Any ideas of what this is about? Faulty tests, chemical?

😫😞