What Causes Stomach Cramps And Scanty Period?

I am 22 years old I live with my long term partner. I was on the pill up until september and now dont use and contraceptives. After I stopped the pill I started having regular periods. Last week I started being sick in the mornings and feel sick quite a lot at night before I go to sleep. I also sleep around 8 - 9 hours a night but I always feel tired. My last period was 5th feb but i was only bleeding very light for around 36hours. I never have had period pains before but had severe cramps whilst I where bleeding. Please could you advise me thanks