13dpo my bfp was soooo light it would have been negative (on a FRER!) on 12dpo
As for triphasic, it doesnt necessarily mean anything. I had several triphasic non-pregnancy charts (especially if you live somewhere where it suddenly started getting warmer over the past couple days...)
Cycles with NO shot at pregnancy whatsoever, clearly triphasic (DF was overseas, there was no chance of even an oops!)
For example -
http://www.fertilityfriend.com/home/...rl/?i=3551927& was nearly triphasic, and DF was in Iraq from 3 months before then until 2 months after
http://www.fertilityfriend.com/home/...rl/?i=3518943& was CLEARLY triphasic and DF had left at the beginning of the cycle before that (but that chart is very messed up due to weather problems and air conditioner problems)
It was actually really common for my temp to jump around 10dpo and stay up until the day that AF came.
My pregnant cycle -
http://www.fertilityfriend.com/home/...rl/?i=3659120&
it jumped at 7dpo rather than 10dpo (after very tight pinching sensations right where an early ultrasound confirmed she implanted at 6dpo)