When Should I Be Worried About Pelvic Pain?

I’m about to be 35 weeks pregnant (4th pregnancy). And for the past 2-3 days I’ve been experiencing something that I’ve never experienced before with my last pregnancies. I get this sharp/shooting pain sometimes randomly and sometimes when I stand up and walk. It’s ABSOLUTELY EXCRUCIATING pain, to where it has me in tears and stopping everything that I’m doing, thinking that I’m in labor but it comes randomly and is only like for a split second to 2 seconds long. Not long at all. I’m not dilated at all. Im still closed, thick, and high, I just got checked yesterday. I understand that my body is stretching and preparing for labor. (Also considering I’m very petite) But when should I truly worry about what I’m experiencing. And what could I do for it?