Ay mommy, that does look like it could be your mucus plug, parang sipon talaga siya but usually it's thicker and more gelatinous, sometimes with a bit of blood streaks (we call it "bloody show"). At 37 weeks and 5 days ka na, it's possible, pero since you're not 100% sure, best to message your OB or go to your clinic para ma-check nila talaga, a few of us moms panicked din thinking we lost it early, kaya better safe than sorry! Keep an eye out if you get contractions or more discharge after, but otherwise you're at a good gestation na. Let your doctor know today lang para they can monitor you, okay?