Start of labor?!?!?! 😁🙏

As of yesterday I started having very light brownish discharge but it is definitely way more noticeable today. I'm 38 weeks 5 days and I'm also having extreme pelvic pressure and lots of lower back pain (tail bone area) but so far I have NOT had ANY contractions. I did have a pelvic exam yesterday and I was 50% effaced and a "tight" 3cm,  Could this be the start of labor or is it from the exam? P. S. I've already had 4 pelvic exams before yesterday's and I didn't have any bleeding or brown discharge from them.