My boobs felt really really sore about 3 days after conception. I tested positive about 7 days later approx 10 DPO but it was very very faint... had a much darker line 2 days later. I knew I was pregnant though, well before AF was due (I ovulated a week early). So you can feel pregnant a few days after conception (especially if you know your body really well). But remember that everyone is different and some people don't even suspect until after AF fails to come and some people's bodies trick them into thinking they're pregnant...symptoms are a LOT like AF coming.