I'm feeling light headed, almost black out every time I stand up. Severe painful cramps in my back and lower abdominal region that have been going in for a week and are very painful today. My period has been late, had what I thought was the start to my period a couple weeks ago but only bled for a day. I'm bleeding again today two weeks later, not my normal period schedule. Something feels "off" in my body. I've been very moody, change in appetite, foggy headed. What could be going on?