I sometimes get these weird sensations in my head?

This usually happens at home. Randomly, I get these head rushes. It feels like there is energy running to my head, but I think it is just a lot of blood. When these head rushes happen, my entire head feels warm, and everything becomes blurry. This only lasts for about ten seconds. It normally happens when I am standing up. I don't know why they happen, or what it is really. My family has a history of cancer (1 of my aunts died about 4 years ago, and 2 uncles are dying from cancer right now) and I am hoping it is not cancer. Can someone help me please?