If this is the way it has always been for you, then it's normal. You might try charting the changes in your cervical mucus to find out if you ovulate at mid point or at two weeks. It will be useful to know when you come to try to get pregnant.
Everyones cycle is differnt. I used to have the implant with caused me to have my period for a whole month, at one point I only had it 4 times in a year but it was heavy and for a very long time. I think u r fine and have nothing to worry about