I might be pregnany and I need help?

I have been on Yaz for about 2 years now, and the past four months I spot usually like 2 days. This month, it's lasted for like a week and I am having some breakthrough bleeding too. At night I usually feel sick and feel like I might throw up but don't. And lately I have been really hot. My period is in a week and two days ago I had a blood test done to see I am pregnany and it came back negative. Could I still be pregnant?