Since getting a faint positive on Tuesday (yey!), have poas at every opportunity. Using the internet cheap tests I had v faint lines from Tuesday - Friday.
But the fun began yesterday (Saturday) when I cracked open the new 50 (yes, 50!) tests from the internet and have already used about 15 in two days, plus a good few OPKs! 
The lines have varied, and I've managed to confuse myself by trying to assess the relationship between:
time of test,
strength of urine,
time since last test,
liklihood of test having more/less dye than average!!! 
It's driving me insane. The lines are still pretty faint (nothing like the control line, and this evening's, using quite weak urine was super faint - which doesn't seem right at 14dpo).
I'm ashamed to admit this , but to make the process scientific, I have labelled all the tests with dpo, time of test and strength of urine. Then I covered the lables and arranged them in order from faintest to strongest just to see if there is any correlation between dpo and strength of line (I should add this is just with the tests from today and yesterday!). The trouble is, when you do 5-7 a day, there isn't that much variation. This is madness!!!!!
I've had chemical pregnancies before and never made it past 5 weeks, so totally paranoid. I'm now convinced that I "peaked" last night, and its been going downhill since then.
Someone please tell me to stop testing! Is there anyone out there as bad as me? :)