What Causes Delayed Period With Cramping, Nausea And Diarrhoea?

Hello doctor, In May my sweetie and I decided to try and start a family. That period was May1st through 5th like normal. Around May 20th my breast swelled up and were sensitive. But on May 26th I had an unusual period. This one was early and a lot heavier than I have ever gotten plus it was only two days. Also I had super cramps and I do not cramp bad at all. I took a test to see if maybe I was pregnant because I had an unusual discharge also. The test was negative. My breast did go back to normal. Since I counted that as a period, my next one should have been around June 26-July 1. (All my periods start from the 30/31st to 2nd of every month. Except the one mentioned in May) So now I am experiencing a late period by 4days to a week, negative pregnancy test, cramping on and off, nausea without vomiting, food aversion, diarrhea, and a rash that comes and goes on my chest to my naval. I am not sure what is going on because my body doesn t feel like my body anymore at all.