Girls can you help put my mind at ease

Caitlin
I don't know what to Think 
Yesterday was 10dp5dt and everything was good the test line was a shade darker than the control line so I was happy. Yesterday my boobs were super sore but last night I had some craming and lots of lower back pain which contrinued throughout the night.
Today I woke up cramps have somewhat gone away but back pain is still noticeable, so i decided to POAS again. And it seems to me that the test line is lighter than yesterday.
Does that happen once it gets dark? Should the test line continue to get darker? SHould I be worried that my hcg are dropping? 
Yesterday
Today below