Hi and thanks for using the forum.
Congratulations on your pregnancy. Some cramping early on is normal, so this may be nothing to worry about. If you start to experience severe cramping or bleeding, then your need to let your ob/gyn know right away. In the meantime, start taking your pre-natal vitamins if you have not started already (one that includes folic acid) and set up your first ob/gyn appointment (they usually want to see your at around 6 weeks or so) to start your prenatal care. Good luck.
Bridget
I had this when I was pregnant, its you're uterus just contracting and the egg implanting. Feels weird but as long as the pain isn't severe and there's no bleeding then you should be fine. If the pain suddenly becomes one sided, sharp and severe than contact a doctor :) but congratulations hun!