Had unprotected sex a week before my period was due i am now 2 days late with mild cramping and feeling naseous could i be pregnant?

Possible pregnancy: There is a chance that you could be pregnant, but there is also a chance that you could be anxious about what happened and the stress alone can cause your hormones to be such that it could affect your menstrual irregularity. You can do a home test, but i suggest you repeat it at least two times at least a week apart. A blood test by your doctor, if you are a week late. Good luck.