Anyone get dark/almost pos OPKs in luteal phase? (10dpo)

[hopestruck]

Has this happened to anyone? For the past 3 days I've taken OPKs and watched them get darker and darker. Today's and yesterday's are both a shade away from being positive. HPTs are all BFNs.

I've heard you can have another LH surge right before AF, but mine's not due for another 3-4 days yet, at minimum.

Anyone have any ideas what this means? normal hormonal fluctuations? help!