Help. Sharp left lower pain

Hi Ladies, I woke up this morning with a sudden sharp pain at my lower left andomen just above the pubis area. It disappears when I lie die but is so painful when I stand up and walk. No bleeding and cramping. I sent my OB a message but she hasn't replied. Pleas let me know if this is something you've experienced. Is this the round ligament pain? Do i need to go to yhe ER. By the way this is my first pregnancy im at 13 weeks and 3 days. Appreciate tour help