Pregnancy symptoms?!

Does anyone know how long it takes to conceive? Can you start showing signs right away? I don't know if it's all in my head but this month has been up and down with sickness, especially nausea, bloating, soreness in the breasts. I'm in the last 2 days of my fertile window and been experiencing these symptoms again today. I thought last month I was pregnant because of similar symptoms, vomiting 2 out of the 5 days I was nauseous, AF was late and when it did come it was only 2 days and very light bleeding. Was wondering if anyone has ever experienced this?!