Cramping at 18 weeks?

Betthany • 22. Married my husband 6/28/14. Expecting our first little boy 1/8/15. Stay at home wife currently.
Im exactly 18 weeks today, and have been experiencing some cramping. As a first time mother, every little thing seems to spook me (I try not to stress but you know how it is!) I was just wondering if this could be the round ligament pain or something more serious? Is anybody else experiencing this? It's not severe, just uncomfortable.