Period 4 days late, but 4 days before due period i had very light flow for 2 days only. since then there has been nothing. tests are (-)ive. advice?

Okay: It could be that everything is okay and there's nothing to worry about nor is there anything wrong. It could just be a light period. If you're not pregnant and there's not much else to worry about.

Period: Those two days were probably your period although clearly a light one for you. You can trust the pregnancy test at this point. If you would like more menstrual cycle control then consider birth control for cycle regulation.