Hi my period was due on jan 17 i had light spotting for three days and that was it. i took 4 pregnancy test and they were all neg could i be pregnant?

No: It doesn't sound like you could be pregnant at all. 4 negative pregnancy tests is quite definitive. If you are having unprotected sex and don't want to be pregnant, consider seeing a clinic or doctor for birth control. The birth control pill is great, it helps regulate your cycles and decrease pain and bleeding with menstruation. Also the iud is a super effective form of birth control.