I have been spotting for at least four days now and still no period, i did a pg test last night and it came back negative. what is going on?

Menses: Period can be light-heavy. If it is according to your expected day then don't worry. Menses is every 3 to 5 weeks, 9 to 13 a year, lasting 1 to 8 days. Keep menstrual diary and see doctor if your periods does not fall within these parameters. Some people may skip a period. If no period or spotting x 2 months and not pregnant then see doctor.