First time using charts

My doctor recommended I do bbt charts because of my irregular cycles. I take opks too. I don't have a clue what this chart means. Fertility friend says my chart indicates that I haven't ovulated yet, but why the dip in temp? I have taken 3 ovulation tests today (9am, 11am, 5pm) all negative. I have cramps and such, and ewcm. Any input would be great. We haven't dtd once during the fertile days, just wondering if there is even a point at this point, or should I just toss out the whole month as a dud.