Hi thanks for your question.
Since your periods were over due by few days there could be two reasons for your vaginal bleeding and pain.No 1.You had concived and lifting heavy load triggered abortion
and your still bleeding because of abortion.
The second reason could be your periods were over due,endometrium (linning of uterus
) was ripe lifting heavy load triggered your normal periods.I would suggest you to wait for the days your normal periods remains.if bleeding still reaims continue,it is then abortion and you should consult nearby gynaecologist for further management.
Hope this answers your question.