Does a woman have one ovulation day or three?

I have the App called, "My Days" and it says that I have five days of high fertility and one ovulation day. However, parenting.com and other sites, such as WebMD say that I have three ovulation days. I'm really confused and would like to know whether a woman has one day of ovulation or three and how it works exactly (any references would be great). The reason I ask is this: I go by the, "My Days" App and I had intercourse with my husband the entire week of high fertility, except the day (the 25 Feb) when it says that I ovulated. I'm wanting to know if there's a chance I could still be pregnant. Also, many sites say that when a man ejacluates into a woman, it takes up to three days for the sperm to reach the egg. Does anyone know if this is true or not and if this is the reason why many sites say that a woman has three ovulation days? If not, it's okay. I may have to make an appointment with my doctor.