Pain from under belly to anus

Hi Mummies. I am on my 26 weeks tomorrow and i have been having uncomfortable pain from under my belly and the pain spreads to my vagina, till my anus. The pain is bearable though and it comes and go. I have been having this pain since yesterday. No blood or waterbag burst. Have any of you mummies felt that before? I am kinda worried if that is a sign of contraction. I do not wanna go to preterm labour.. 😭