round ligament pain?

Hi ladies, I am 17 weeks today and a FTM, since Friday I've had only what I can describe as pain 'inside' and on my right side of my stomach, I can't lay flat on my back anymore because it hurts and it feels like everything is being pulled. This morning I woke up with a really intense pain on my right side which lasted for about 5mintues I haven't had it since or before. As I'm a FTM I don't really know if these pains are normal? I've read about round ligament pains and it's probably them but do they really last this long? (3 days) I thought they might come and go..