Pregnant or deff not?

Could i be pregnant still, Iv had three days of on and of bleeding, going from spotting pink to medium heavy brown back to pink only when I wipe. Iv been so tiered since Saturday, lower back pains and constant dull lower-stomach cramps, feeling sick and also diahrea, Iv taken two pregnancy tests both of which were negative but think Iv actually tested way to early. Could I still be in with a chance? I AF is ushally around 7-8days and really heavy so the 3 day bleed Iv had was nothing atall like my usual AF. Anyone had anything similar? I'm on month 16TTC 😕👎🏻