What does it mean if I have a cold and I also feel lightheaded and I feel like vomiting? What do I need to do to get rid of this?

You have a virus, most likely - cold, flu, or intestinal virus, maybe with a sinus virus. Which 'flu' covers pretty well. You drink lots of warm weak liquids, stay warm, and rest as much as you can, avoid contact with others (so you don't give it to them), and avoid lying flat. That's about it for the cure!