I don't believe there is a set schedule for when symptoms would start. Personally, I'm chalking anything prior to 5dpo as gas or something I ate/drank. During 1-5 or 6 dpo, the cells are still traveling down to the uterus for implantation and I don't think your body is doing much more than producing progesterone to get the uterus ready for that. I'm no doctor, though, but I'm not counting on anything happening in 1-3dpo. But that doesn't mean it won't happen to you!