Negative making me negative!

Just to give you a bit of background been trying since Oct/Nov but had a casual approach to it and a "it will come when it is ready attitude" however since coming off the pill my cycles have been very varied and had real trouble telling when I was ovulating, not good at reading the old CM. Anyhow, this month decided to get ovulation strips and give them a whirl. Made sure we spent lots of "time" together before during and after the time I ovulated and have been waiting out the dreaded 2WW (why does it feel like a 20WW!) and did a test this morning....BFN.:x Was gutted. Have been naughty and been symptom spotting but most def have been very lightheaded, nearly fainting a couple of times and had various other twinges, cramps etc. I used a Boots HPT and was wondering if anyone else had tested negative off these at 12/13dpo and still been pregnant. I looked on the back of the pack and saw that they advise testing on first day of missed period, but with mine being so haywire wanted to test as early as I possibly could. Think I am due on around middle of next week...judging from previous cycles but never can tell wth me. So I suppose my questions are:

1) Has anyone tested neg off a Boots own HTP and then got a BFP later?

and

2) Do you think I should just wait it out and see what happens next week and try testing again if AF does not appear- or should I leave it longer?:\?

Would appreciate some help! xx