Faint bfp's/bfn's?! Miscarriage?! Advice and guidance needed please!!

Liz
Ok, posted earlier, but I thought it would make sense to put it all together to try and get some advice and work out what's going on!! 
​So thurs, Fri, sat and sun I got faint bfp's (all fmu, with another test Fri being in the afternoon) all with 10miu, then today, with a less sensitive test I think I got a bfn, but some of the other ladies think they can see a line! Posting pics below. I've got really sore boobs, which I've never had with AF! I was due AF yesterday. Been having mild cramps too since thurs. could my hcg numbers be going down because it's a chemical pregnancy? Or were the bfp's wrong? Help!! What do u think?!