Cm check? 10dpo.. Normal?

Danielle
Has anyone had yellow tinged cm before getting a bfp
I'm 10dpo have had backache pretty much since OV. It's been there, not always really achey but today I've been majorly achey! Slept 13 hours plus a 2 hour nap in afternoon, which is really unusual for me. 
Tonight in shower I have noticed some unusual yellow tinged very stretchy cm, and was curious to know how many people have experienced this before getting a bfp ? 
AF isn't due until 1st xxx