My Period Was Late By 6 Days, I Ended Up

My period was late by 6 days, I ended up getting it anyways but leading up I was experiencing stabbing pains occasionally on my left side of my lower abdomen along with headaches. During my menstrual cycle I expernced a heavy low than normal accompanied by cramps, stabbing pain from before, and an itchy rash formed on the front of my neck slightly travelled up to my ears. Now I have bad neck pain and a headache with occasional abdominal pain still, and the rash still present as ever. Is there any correlation? Or anything that can explain this at all?