poking sensation

Hi i'm at 18 weeks. I'm going to see my OB sa tuesday pa kasi I am not going to panic haha, but do you guys ever felt a poking sensation na may slight pain sa puson. Nasa baba ng navel, episodes lang, hindi continuous. Di ko alam if napagod lang ako or baka normal naman lang sya. Baka muscle spasm lang din kaya consult ko muna mga momshies dito before i ask my OB.