Possible implantation or normal period??

Hi ladies , I have a 28 day cycle and currently on 12/13Dpo , this past week till now I’ve been experiencing cramps like never before . Tested on 8dpo and 10dpo and both came back negative so I kinda assumed these are cramps related to my period coming and ruled out pregnancy.

Now , I’m normally a heavy bleeder especially on day 1 of period . I’m currently on 12/13 Dpo and started my “period” on the exact day I was supposed to start. However , my flow is very very light mind you it’s day 1 and I’m still having cramps . Could this be normal cycle or possible implantation?? Ps I’m scared to take another test because blood did come through on the exact day so it’s not like I missed a period however the flow of it just doesn’t seem right.