Hay, congrats sa 40 weeks na! Honestly ang mucus plug ay pwedeng mag-appear with or without blood, kaya yes, possible na yan na siya, usually yellowish or clear and stringy talaga, pero bawat mama different. I'd definitely text your OB or go in para ma-confirm lang, especially since may tummy pain ka pa kahit nawala na, kasi they need to check if baby is okay at if you're already in labor or close na, a few of us waited lang without confirming at naging mas worrying lang, so better safe!