Early period or implantation?

Hi everyone, I'm 37yo who has been TTC for 7 months. Had early m/c in July only 4 days after finding out I was pregnant (period was one week late when tested) but had very low hormone reading.

Tested Thursday afternoon 10 days post ovulation and with 6 days till period due. BFN no surprise.

I'm very regular with my period and notice changes in my body very quickly - tonight I was very surprised to find blood after having sex with hubby. Not bright red but enough mixed in with leftover spunk to leave me wondering. Typically I experience very large hard tender boobs before period or when preg (don't have currently), bleeding gums when preg (they bled when brushing teeth this morning), achy back for both (check!) Plus I've been feeling slightly nauseous every afternoon this week (don't experience this during ovulation or period) Plus I'm feeling a bit crampy right now.

Could this be the start of my first ever early period (not due till Tue, so 5 days early??) or symptoms of implantation 10 days after ovulation?

Thanks in advance for replies.

Feeling hopeful but realistic.