advice never had implantation bleeding before with last pregnancy

Bre

ok guys dtd on 5/18 during my fertile week. one week later I started getting cramps. They would come and go every day. sharp twinges here and there too. Last night I was super nauseated that I couldn't move. This morning I woke up with cramps again and brown discharge. Thinking it was my period I took appropriate measures and put a tampon in. Lunch time I was able to change and there was hardly any on the tampon, dark brown and dark dark red. I put a pad on and have since had very minimal bleeding. I also came down with diarrhea today (sorry TMI) so bad that it hit me like a train...AT WALMART! 🤦🤦 I've had slight cramping and a weird headace all day. I'm also 2 days late which never happens. Any insight?