My LP is 13 days and a got a very faint positive at 11 DPO, so faint that my DH thought it was still negative. I didnt get a good positive until 15 DPO, and yet the test line was still much lighter than the control line.
I think 10 DPO is very early, because some embryos dont implant until 7-10 DPO, therefore you could have only just implanted which would be why the test is still negative. Id test again if your AF is late because it is possible you are pg, but it is just too early to tell now.
Goodluck over the coming days, I hope you get a BFP this month.