Left side cramps? (Help)

Erykah • I love myself some pecans 😂😂
I woke up this morning. It's been 12 days since I had sex on my most fertile day and I also had sex the day after. I don't know if I spotted. I didn't really pay attention, but I have cramps from my left waist and up to my shoulder kind of. My period should come on the 31st. I'm not having any pregnancy symptoms I don't believe. Help, please?