Blessedatlast said it well Temping and charting your cycles is an excellent way to see what is happening with your body and help pinpoint when you ovulate. You need a few cycles to start seeing patterns though but it really is helpful in most cases. I have quite a few good cycles linked through my signature. You can see them all in the chart at the top of the screen which is an 'overlay' of my charted cycles so you can see patterns.

CD1 is classes as the first day of full-flow (AF). So spotting is not CD1, it must be full flow. Providing you had full flow last Thursday when you said AF arrived, you would now be at CD7. I usually have a 28 day cycle too but I ovulate anywhere from CD14-18. It can and does vary each month. I used digital ovulation test to help me determine when O is nearing too but I now have quite a few good charts so I could probably just BD between cd14-19 and our chances of conceiving would be pretty good.

I highly recommend charting and temping (and using OPKs for that matter!) if you really want to increase your chances of conceiving quickly.