Hi..is totally normal...the samething happend to me but at the difernce I had a ivf done..I started w the spotting 3 days before getting my heavy period..I ended in the hospitall because the pain was horrible..I did also a research and it says that low progesterone in your body may cause spotting then full period...hope this help!!
it is normal to have it happen that way, especially if you were a couple days late.. I would not worry unless you start to have pain, or the heavy bleeding continues longer then a normal period of time.
its normal to spot and than start periods. dont worry