Pregnancy cramps?

Ladies! I am 5w5d pregnant with my first babe. The past 2 weeks on and off I have been having painful cramps. They are either on my right side or left side but never both at the same time. I've read that this can be normal but these aren't exactly "light cramps." I've also read about ectopic pregnancies but those cramps are only on one side. Has anyone else experienced this?