Sharp sudden pain?

I’m 28 weeks tomorrow

I was walking around shopping (almost quick walking maybe) and all of a sudden my abdomen gets really hard and I get like almost a sharp shooting pain in my lower abdomen. almost like gas pain but worse and between my belly button and vagina. (so in the middle not on the side). If I pressed on it during the pain episode I felt like I wld pass out from pain).

It lasted about 5 min and I had to go find a fitting room to sit down. After that it went away and now it just feels sore/tight in that area but no sudden sharp pain again.

No bleeding.

What could have caused this? Round ligament pain? Or worse (placental abruption?) I have an anterior placenta that’s why I’m so worried.

Any insight would be greatly appreciated! If it happens again will probably call MD