Right side pain right below ribs

I'll be 28 weeks tomorrow and i woke up around 1am and had this pain on the right side of my belly, I thought maybe it was the way i was sleeping so i switched sides and now we are more than half way through the day and i still have this constant pain, im not sure whats causing it and the pain gets worse when i walk. Has anyone else have this happen to them before, im getting kinda worried now, i emailed my doctor and just waiting on a response from her.