Clomid-positive cheapy-negative first response. Help?!

[Nopee]

Hi,
This is my first post, I’ve only just signed up because I really need some advice.
I took clomid last month as I have PCOS. This was my second cycle (first cycle, I fell pregnant but miscarried at 12 weeks last year).
I had those cheapy 10ml sensitivity tests so I tried one Over the weekend and it was positive all be it at the end of the time frame window! So I used another 5, all positive but again right at the end of the time window. So this morning I tried a first response and it’s negative :,( I don’t know what to think! The timeline just doesn’t make sense to me. This is my dates.....

Provera 20mg taken 15th-20th July
Very light period started 22nd July
Clomid taken 24th-28th July
Positive opk 9th August
Positive sensitive pregnancy test 24th August
First response negative - today (28th August)

Surely a first response would be positive 4 days later?!
What is going on? Could I be pregnant?! We’re the tests wrong? I’m driving myself insane right now!
Literally anyone to talk to about this right now would be brilliant.
Thank you
X

Just thought I would add, although I got a smiley opk on the 9th of August I didn’t really feel like I was ovulating around then. However I did feel like I was ovulating around the 19th of August?! It makes no sense :(
I just want to know if there is any chance I could be pregnant or if the time scale a weak test lines would mean that either they were dud tests or that it was a chemical?