PLEASE READ

Please read, I don't know what to do.
So for the past month I've been feeling nauseas here and there and have been having a very big loss of appetite, I have loss some weight, my clothes are starting to look big on me too. I also have a history of anorexia. I had unprotected sex on September 19 and used the pull out method and I was not on my fertil days until 4 days later it happend. I had my period on time; infact, 2 days earlier. But after it ended on the 7th day per usual, 4 days later, I had very very bad nauseas and almost threw up that night. I have also had constipation and had diarrhea 2 days, different days though. I am beginning to get very very worried; I don't know if I might be pregnant or just my anorexia starting up again.  I don't know what to think or do. Any advice?