6 days late, 5 negative results, but all symptoms!!? Help!

Hi all, I was due for my period August 26th, I am now 6 days late. I have an 9 month old that I exclusively breast fed until 7 months. Since then I had two periods and they both were on time, like always. (I'm never late)

This time around, I am late!! A few days before my expected period I had a little bit of pinky colored blood when I wiped and tons of discharge. I didn't think anything of it until now, as I am having lower abdominal cramps and lower back pain. The past few days I have felt like I have been hit by a truck!! I can barely keep my eyes open. I have taken 5 different clear blue tests and they all have been a bfn. Although one digital test showed up neg., then later that night the digital wording went away? (That was my most recent test)

Anyways, could this be pregnancy!? Has anyone ever experienced this? This would be my third baby, and with my other two I would get a straight positive rigt away and early!!

Thanks youuuuuu