just some input

Co
My fiancé & I are ttc. This would be the first round of trying, we had sex last Saturday& Sunday and with work he's gone all the rest of the week. Since then I've been feeling crampy, nauseous every now & then, and my boobs are tender and look more full. Literally everything I'm describing are my pre Aunt Flo symptoms but she's not supposed to come for another 15 days or so. Has anyone had symptoms show up this soon? I feel like with my last pregnancy I knew as soon as we conceived. Anyone have input? Going/gone through the same thing? Thanks!