I am 22yrs old and got married on the 23rd August this year and have never been sexually active until that time, I have been on birth control for 6 months and take it religiously except for 1 or 2 days when I have been 2 hours late taking it. 5 days after our wedding I started getting really bad nausea this lasted on and off for 5 days, since then I have had the following off and on: lower back aches, cramps, sudden rises in temperature at night, frequent headaches, I was due to start my period last week which is always on time and 5 days heavy however It was 1 day late and only lasted 2 days, it then stopped for 2 days then started lightly for a few hours then stopped again i woke up this morning and its light again but hasn't lasted long? Which is not normal for me. I have taken 2 pregnancy tests both negative, over the weekend my nausea also started again on and off to the point where I have to sit down on the floor near a toilet until it passes. What is causing this could i be pregnant?