hi my last period began on march 13,2013 and my cycle is 26 days. my period was suppose to come on april 7,2013 but it has never showed up. I am now 4 days late of a period my breast are sore and tender as hell, i feel nauseous all times of day and night but can't puke, i feel slight cramp feeling, very tired. I took 2 home test but both read negative and i took them a day apart. Im totally confused because ive been pregnant 3 times and one live birth and never have i experienced this. And my period always comes on time. please help me!!!!