Help me please lol

So I'm a first time mom obviously lol I'm 37 weeks and 4 days, I've had the feeling asf if I had to poop for like two days but nothing happens, and have been having parts of my mucus plug constantly come out for three days, small cramps/ Braxton hicks here and there, my back pain has increased terribly for no reason. So my question is how do I know I'm in labor when it actually happens, I have a very high pain tolerance and just tend to blow things off. I'm afriad I won't know when labor comes.