I Took Emergency Pills On 27th Sept And Then Also

I took emergency pills on 27th Sept and then also when i was fertile(according to my calender) on 2/10/2015, so two days later i had some bleeding for about four days. I have since had 2 pregnancy tests and all are negative the latest on 30/10/2015. What could be the problem. Its 4/11/2015 and the last time i had my periods was on the 18th of September. Could I be pregnant? Could it be an ectopic because I have been having some dull pain that comes and goes on the left lower abdomen.