Mucus Plug

I just lost my mucus plug at 38+4, I have been having very sporadic contractions with exercise for about a week but nothing with any regularity or pattern. At 38+2 I was “soft and 1cm dilated” per my OB, after that exam I had some rusty brown spotting which I was told is totally normal. I’m just wondering how many people lost their plugs and didn’t go into labor for days or weeks or if it’s a pretty sure sign that I’m gonna go into labor within a day or two.