Cramps Right After Sex??

So last night hubby decided to surprise me with sex while I was sleeping. I woke up & of course finished our "business" but right after as we laid down next to each other I started to experience very intense cramping. It took a few mins & a few belly rubs from hubby for it to go away. I've never had this problem before so I don't know exactly why but was wondering if that can be a sign of early pregnancy. Thank you for the help!