What Causes Vomiting Sensation, Headaches And Cramps?

I have a son already but when i got pregnant the symptoms didnt appear till i was around 5 months . Me and my boyfriend have had unprotected sex about a week ago and he mentioned he might have came inside . These past 3 days , i have been feeling of throwing up . But it never comes out . I've been having uncontrolable headaches . And Just today i've had cramps . My period beings every month on the 1st , but I am very afraid i might be pregnant again . Can you tell me if I'm just feeling symptoms for my period , or am I pregnant ?