Any time in the pregnancy you have discharge-you need to immediately consult your physician. Many times women don't realize they have lost their "plug,". It could be labor, but also could be a sign of something else. At 37wks, you should be in the clear to deliver, without major complications due to immaturity of the baby.
you probably lost your mucus plug dont get too excited i lost mine several times over aboout 3 weeks before i went into labour, If you lose it and your body is not ready it will rebuild the plug, if the plug comes out WITH blood in it, that means you are probably close, however I was like you i had NO idea what to expect, if you go into labour you will notice lol only 5 percent of people have painless labour If you really are worried about going into labor time your contractions, they will be regular, get longer stronger and closer together, your breathing will tell you also, if your breathing feels laboured during contractions, or if you cant walk or talk during a contraction, you are probably in labour, your mucus plug may fall out several times in lar4ge quantities before you are in labour but is a sign things are progressing so just keep an eye on everything, things are just moving along as they should as far as sex being uncomfortable, everything and ESCPECIALLY sex is uncomfortable in the last weeks, if your cramping during sex dont worry, this is normal the semen, and your orgasms both make hormones that can trigger contractions and cause cramping and discomfort