What Causes Delay In Periods,constipation And Sleeplessness?

I am 24 years old, unmarried and havent had an intercourse.I have always had a normal menstrual cycle since last 8 years.My problem is that there is 7 days delay in my periods for this month.Last month history:menstrual cycle was about 33 days ,my period duration was of 3 days with very less flow and at the start of the first day I had very painful experience there was vomitting and constipation at the same moment for 2-3 times.And along with that the blood flow was very abrupt Except the first day the pain was absent or mild.This month:delay for 7 days now,sleepless since last 6 days,have taken H-vit Forte for hair and skin health(10 days) till now.Please help understand the problem and guide me