I was testing every day from 7dpo (I was obsessed) and I was using internet cheapies, Clear Blues and FRERS and I was consistently getting negatives. It wasn't until the afternoon of the day that my period was due that I got my BFP.
Aw fingers crossed for you. It's difficult when it's taking a while and it always seemed to me that everyone else was falling pregnant just by walking past their partners!! Since having DS I've realised through all the groups I've been to and friends I've made that there are many people who take longer than you realise to fall pregnant. It's not really helpful but sometimes it's nice to know that you're not alone and it's quite common for it to take longer than you'd think/hope/want.
Failing that, they can so wonderful things to help now - DS is testament to that.xx
We dtd on count day 11 (the only time that months), i ovulated count day 14 and got my bfp count day 28, the day at was due. I did test on count days 25 & 26, and got a line so so faint it looked like an evap on day 26.