Help!!! AF due tomorrow but got A BFN

I'm up to day 29 of my cycle, my past cycles have been wacked and I don't know what day is O day or what day to expect AF.
Past periods 
34 days
35 days
21 days
29 days current cycle AF EXPECTED TOMORROW. 
Have been having nausea (same as baby #1)
This morning woke up with bad back and lower abdo pain.
BFN clear blue test just now.
Any other stories like this