Is breakthrough bleeding a period or what?

hi there i want to know if anyone can help me i had my period on the 7th of october and it finished on the 13th october we had sunday monday tuesday and wednesday nights and than thursday morning i had blood not enough for a panty liner about the size of half a 5 cent piece everytime i went to the toilet for 5 days im really confused and i should i have got my period yesterday but i haven't go it could i be pregnant? or is that bleeding a period and to wait till what the month is up and than i will be due the 15th of novermber very very confused?