Implantation or ovulation bleeding?

Lauren β€’ Married August 2014, boy mom, first πŸ’™ born July, 2016, #2 πŸ’™ born December, 2018.
This past Friday (CD21) I had a bit of blood mixed in with a surge of pinkish egg white cervical mucus. It was just one heavy gush right when I got out of the shower, then no blood since. I had been doing OPK tests since CD 10 with no clear positive. Days 16-17 were almost positive, but not quite as dark as the control line. I've been trying for 9 months now. Could it be ovulation bleeding or implantation bleeding? Thoughts / advice welcome! I know the best thing to do is also the hardest...wait until AF is due then test. But I'm so impatient and curious!!