What Is Causing My Nausea And Irregular Menstrual Bleeding?

I had what i thought was my period the first and second of the month but it was really light and lasted about an hour each day. Then a week later I felt like my period was about to start again because i was cramping and had back pains. Then when i went to the bathroom to check if i had started, there was a pinkish discharge in my undies. Its been about 3-4 days since i noticed that. Yesterday I had light bleeding for about 20 minutes and i've been feeling bloated and like i'm about to puke. What is wrong with me?