Sausage allergy?

Whenever I eat Italian sausage for dinner, I throw up the next morning/afternoon, even though I didn't eat anything for breakfast at all ... I have eaten store bought sausage and my nana's homemade so I don't know if it's the wheat that could be in the store bought, but I haven't thrown up with any other wheat products, only sausage ... I was just wondering if anybody has experienced this or knows what it could be caused by? Thanks!

I've never thrown up after eating sausage, but I get this weird feeling in the back of my head, like I've been hit there, but it's a dull pain in my head. My headache usually gets so bad that I have to sit down because the room spins and I can't think. It hurts my head to breathe and to take steps. My face also turns red during one of these attacks. I hope someone else reads this so we can find out what's going on.