I came on my period this month 4 days early it was lighter than usual for a full day an didn't become heavier till overnight i came on 3 days ago

And?: Not sure the question. If it is " is this normal?", the answer is yes, can be. If more painful or persistent, see a doc.

Abnormal bleeding: You may have some changes in your menstrual cycles that are normal. Some women will have some spotting for days before starting a heavy cycle. I would monitor your cycles for a while to see if this is a normal pattern for you. If it becomes a pattern, i would recommend you talk to your doctor about this.