Oh, hon. Try not to stress, until you have a reason to really stress. My beta at 12/13 dpo this time was actually 48 or 49, and by 15 dpo, it was nearly 170. I absolutely despise those curved handle FRER's. They do NOT show progression, and I find they have very poor dye saturation. Those tests didn't get really dark for me, until I was at least 17-20 dpo. If you're not bleeding with cramping, and your hcg continues to double every 48 hours or so, I would ignore the FRER line darkness thing. Perhaps put the tests down, and wait a week or so (I know, I know...that's easier said than done)...but surely you'll have your hcg progression sooner, and that's a far better indication of how things are going.