Short Menstruation

I am 18 years of blood tests are more old.My fine.My period comes exactly one day up or down the same each month. If the first day, it is extremely heavy, then the next day is mild and lasts 3-4 days.
Is this normal? I mean? isn't running?

Yes, it is short, but it is perfectly normal. We are all different (mine is only 4 to 5 days). Do you take the pill? Because the length and can carry the weight of your cycle. I used to have a heavy period for 10 days until I went on the pill. But, yes, absolutely fine:)

is normal.