so me and my boyfriend had sex in feb.dates-9th,16, 17, 19, 23, 25, 26, 27, & 28th) i got my period the second week of feb. on the 11th. it started of really light and then was kind of dark but not real dark and each time we do it, we use the "pull out method". now its march and we have had sex dates-2, 3, 5, 7 8, 9, 10, & 11) my period was suppose to come march 7th but it did not. it came a week and a day later on march 15? it started really light also. should i be worried?