Im in the same boat and I am 39 weeks right now. I saw a video from a nurse and she made a good point, your water breaking (even a trickle) will run down your leg (if you’re not wearing underwear) because even though your mucus is watery it still kind of sits there. May help determine at least between mucus and water (pee is a different story since that two will run down your leg😂) By all means I am a first time mom and I have been obsessing over this fact probably since 36 weeks so I definitely feel you. I lost my Mucus plug and had my bloody show last week (at 38 weeks) and now starting to have slight cramping (nothing consistent or intense). I’m not sure there is a tell tale sign except trusting your body to let you know. At least that’s what I’m going with bc everyone’s labor stories seem so different from each other.
As a mother of two, 3 soon, I would advise you try not to look into it or focus too much as if your in labour the pain will be consistent and won't stop. You won't be able to ignore once it happens.
Trust me you will know you are in active labor