Hi and welcome to HCM 1.Stress is one reason your period may be delayed. try and find ways to relax and de-stress. 2.Change in schedule Even something as simple as a change in schedule can be a reason your period is late. If you recently switched from working days to working nights, your period is likely to go for a toss as your body is trying to adapt to the change in schedule. Hormones can be quite sensitive. 3.Doing lots of exercise: Exercise affects the menstrual cycle by elevating the metabolism. Metabolism is responsible for essentially sustaining chemical reactions in the body like menstruation. 4.Birth control pills 5. Any medications that delay menstruation 6.Pregnancy: but you have done home pregnancy tests and it is negative, so pregnancy is less likely to cause delay Eat nutrious food, practice meditation, drink lot of water. Wait for another week and if periods wont return then contact a local doctor for proper diagnosis and treatment. Regards Dr Santosh