Get sick after sex, is it bad? good? pregnacy? help?!?

I got my birth control removed two months ago and my hosts been sick and wired and now all of a sudden I'm starting to get sick after I have sex with my husband? Is that normal? I mean I get a head ache that last a short time and then I get like I want to throw up but I don't, is it a good sign, bad? Or a sign of pregnancy@? Help :(