Implantation bleeding

I’m really confused on this 👆🏾 subject. What exactly do implantation bleeding looks like?The day I was suppose to start my flow I think I was only “spotting”. It did not get into my underwear (only a couple of drops) that lasted about 3 days, then later on in the week I was experiencing back pain, sore breast( that usually happens right before my flow starts) nausea and also headaches(I barely get any headaches), and also LOTS of cramps.I tried to do my research but I rather go to other woman for help.