4 days late BFN

Nikki
I'm just wondering if anyone can help me  I am currently 4days late 2negative tests. My cycles usually go from 28-30days, I only have really bad lower backache, extreme tiredness, cramping on and off, nausea now & then & also have creamy white discharge & I usually dry up before AF (sorry tmi). My last two periods I have heavy bleeding for one day and then light/spotting old brown for the rest of it which I've never had before. My and my partner have been TTC for over a year now with one miscarriage back in September. I'm so confused to what's going on as with my little girl I found out the day my period was due & the same with the miscarriage.xx