Got my periods (Irregular)after week of having sex, still feel vomit, no Appetite, constipation. Am I pregnant?

Maybe. If you have been having unprotected intercourse you could be pregnant. To know for sure, check a pregnancy test and if it is negative repeat it in 3-5 days. The nausea, vomiting, lack of appetite, and constipation could just be a gastrointestinal problem. Hope this helps.