That varies on the women. Some people know as little as two weeks after ovulation that they're pregnant while it takes others longer to find out. I think often times during the two week wait we symptom spot trying to figure out if we're pregnant of not.
I think the hormones can affect you right away. I was only at like 5dpo with my first and I started getting dizzy and with both my pregnancies I had sore breasts like you wouldn't believe right away. All before I got a positive test. Once conception happens, that's when the hormones are released and probably even more after implantation!
I only ask because we have been trying for a little while and if my calculations were right we did everything happened in the proper time frame and a week later I was just sitting at my desk and burst into tears for nothing. It keeps happening and I am trying to figure out if my hormones are off or if there is something more to it. I guess I will just have to wait it out.