Ladies, what were your first tell tale signs?

bn ttc #2 for 23 months. Im 34 and dh is 29. I take my bbt every morning alongside opk's. my next af is due Thursday. I have a 27 day cycle and we bd 26th & 28th Nov dec 1st 2nd and 3rd, ovulation occurred on the 1st. I know its not that often but dh works strange hours. Ive got severe heartburn which has lasted on and off 3 days and this horrific back pain shooting down the right side to the top of my leg and had a disturbed nights sleep because of it. Just took a hpt but BFN, no sore bbs, no nausea, has anyone had anything similar? what were the first tell tale signs?