I've never vomited after doing legs, but do remember once strange incident a long time ago. When I was in high school I was doing legs at home and it was my first time training legs in a few weeks. I finished my workout and went upstairs to get my post workout meal which I think was a couple of bananas and maybe some oatmeal I think. Anyway, I sat down to eat but I felt a bit nautious so I was gonna wait for a few minutes to eat. All of a sudden I felt like I was going to pass out. I got kind of tunnel vision and my hearing got muffled. That lasted for about 5-10 minutes and then I felt normal. That only happened that one time and never again.