Have you tried getting 10miu HPTs, they are ultra early preggo tests, much more sensitive then Clear blue and First Response. I got my first v v v faint BFP on these around 8 or 9 DPO.
The ones I got were v v cheap around £5 for 10 which is around $12-15AUD. I had to wait for them in the mail but they arrived the next day. Try babymad.com or google it and you should find something.
Apparantly the ones you buy from chemist/over the counter only detect 25miu or over and more often nearer 50miu.
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