What Causes Spotting After Having Intercourse?

Hi I just had my period about a week and half ago. While in the middle of my period i had unprotected sex with my ex boyfriend well even before that i was feeling sick. Im tired peeing allot feel like throwing up on the daily. Well things were fine and had a slip up and had protected sex 3 days ago and today I am spotting which is not like me to have a period twice in one month its not heavy its like almost tiny discharge balls of blood nothing heavy barely at all. I have a son who is 3 years old and i dont recall any thing like this when i was pregnant with him. But I am a little worried. Could i be pregnant? Would it be my ex whom i had sex with in the middle of my period (says he couldnt go ) but it was unprotected or would it be the guy from 3 nights ago that was a mistake but we used protection. or is it normal? Please help me.