Can anyone help me please

Hi ladies just wondering if anyone can help before I decide to give the doc a call, I'm 31 weeks and 3 days but for the past 2 days I've had constant period type cramp at the bottom of my tummy, baby has been head down for the last few weeks too just wondering if anyone knows what this pain could be had some lower back ache with it too but don't think it's braxton hicks as the pain in my tummy doesn't come and go it's just stayed constant and gets worse if I walk anywhere also had some shooting pains last night going down into my vagina, sorry for the long paragraph FTM and my rainbow baby so worry over anything lately x