I Think I Might Be Pregnant. But I'm Not Sire.

I think I might be pregnant. But I'm not sire. I took a test about a week ago and it was negative. I bled for about 3 days and it was never very heavy. About a week after I bled I started getting sick. For no reason. I puked once one afternoon and the next morning I had to run to the bathroom. I feel like I have pressure on my uterus. But I'm not sure. I was suppose to start my period yesterday and it hasn't come. Please help....