Hello Doctor, I Recently Got My Periods But It Last

Hello Doctor,
I recently got my periods but it last only for 2days and few blood drops on the 3rd day. Usually i get it for 4 days. The 1st day I had a proper heavy flow and it gradually decreased. I was also experiencing a sharp pain in my lower abdomen few days before getting the periods. Is it normal? I was relieved that I got my periods but as it last only for 2days I'm really worried if I am pregnant. My husband and I had protected sex last time. Is there any chances for pregnancy? Also I had an I-pill around 2months ago and had a normal period last month. Is my problem the effect of that pill due to hormanal changes??