May 27 EDD anyone?

Michelle • When I become pregnant it will be my second pregnancy. I had a tubal pregnancy 4 years ago.
Ok so I'm currently "3 weeks today" if I'm indeed pregnant. I'm 7 DPO and CD 21. The only symptoms I've had, is cramping that started at 2 DPO and has been on and off and still happening! I've had this dull ache in my lower back since 2 DPO as well! 
Yesterday morning when I went to the bathroom there was some little specs of blood on the toilet tissue, which I associated with implantation blood. 
Last night my boyfriend told me that my nipples and my Ariola's look darker than normal and have bumps around them. 
I know it's super early but I've been taking sure predict pregnancy tests that show up with only 10 miu of HCG, and I'm still getting BFN. 😔 I know it's still early but I'm just going crazy because I just want to know! LOL 
Anyone else in my boat?