Please Help!!!!!

So My period came 2 weeks late. Abnormal for me. The first day of my Af it was a light flow I had back, butt pain and slight cramps. The second and third day of Af it a was heavy flow. I'm currently on on my fourth day and it is a light flow. I am currently Experiencing Severe Migraines and Nausea I have had these symptoms since about 4pm today. I also have loss weight and have a decreased appetite. Tomorrow is my last day of Af. I'm so confused on what's going on with my body. Should I be scared or Worried? Advice??? Comments?????