Cramps😩

To make a long story short my fiancé and I had sex the morning he got released from jail, and I believe September 1... Anyways both times were u protected and now today September 4th I've been having cramps all day my left side  .  I had light blood 2 days after sex the first time that lasted for 3 days... But it's too early for anything to happen. I just want to know why am I cramping this early and my cycle isn't due until the 14th or 20th going based off my period tracker apps.😩