The average blood loss during a menstrual period is 4-12 teaspoons and a period can last anywhere from 3-7 days. You may notice that your flow is heaviest on the first 2-3 days with some bleeding at night. Of course every girl is different. A heavy flow is considered as soaking through a pad or tampon more than every 2 hrs or having to change more than once at night. This off course is normal for some girls, especially early on in their period. Over time, you will get to know your own cycle and will find the pad or tampon that suits you. I suggest having a pack of super and regular pads or tampons and a pack of liners to keep you fresh at other times. Make sure you change every 3-4 hrs.