i am on CD18 out of a 28-32 day cycle. i had sex during when ovulation should have occurred and the past few days, i have had constipation and a lot of gas and pressure. it takes me forever to go and whenever i do, its only small pieces and hard (tmi sorry) but i read that constipation can be an early sign of pregnancy and happen as early as conception....the reason the poop would be hard is because your body is sucking out every possible nutrient for the baby. i NEVER have this problem, EVER thats why i am wondering whats going on and if i might be pregnant. also been experiencing headaches, slight nausea and some lightheadedness. any advice would be great and thank you ladies!