Pregnant or not ?

Hi lady's my name is heather and I was 31 weeks pregnant 9/10/14 when my baby boy became an angel. I haven't had a pediod or bleed since that 15. Me and my husband have been intimate several times. I have gotten my acne again as well as heart burn, headache on and off and I'm dizzy when I stand up to fast. I took a test it said no a few days ago but I get cramping and I'm no where near getting my monthly. What could it be ? Thanks