I wake up everyday saying to myself: "OK, I'm sure I'm not pregnant" , then I change my mind during the day. The first thing which makes me think I'm not pg, is the BBT. For those who have no clue about the BBT : the Basal Body Temperature is your body temp exactly the time you wake up in the morning from at least 3-4 hours sleep. you shouldn't drink, eat, stand up or cuddle before you measure your temp.
People usually take their BBT daily and save it in a chart to figure out their ovulation day. If you chart your BBT, you'll see a clear rise of temp the day after ovulation. that day would be the 1DPO.
The point of continuing with BBT after O is that it will sink again exactly before the AF. So if it doesn't, that means you are pregnant.
I also checked lots of charts on fertility friend website. so many pregnant charts had another rise in their temp at the end of the cycle, instead of going down for AF, they went up. but  there were also some charts end up with pregnancy that they didn't have much rise, just stayed high.

So every morning I wake up hoping to get a higher temp, but I don't, and that disappoints me. And since I don't "feel" pregnant I definitely decide that I'm not.

I also have a mix feeling that this shouldn't be like this. and I shouldn't be that obsess with the process, and it will happen at it's time. I was just never patient in my whole life.