Is it Jealousy with this girl?

Okay so im a freshman in highschool. There is this girl I asked out that said no but is a good friend of mine. Whenever we meet at lunch and brunch we say hi and what not (nothing more). As i said in another question there was this girl (lets say jessica) who told me she likes me. I said I wanna stay friends and we hang out all lunch and brunch talking away from everyone else. Anyways, I was at the park with a few of my guy friends in our group today. It was a kind of stressful day with STAR testing and everything. The first girl jokingly called me fat today. I told her that was ****** up and she is all sorry now. I am pretty much not talking to her for now and my guy friend texted her and told me that she said she feels like she lost a brother ( i was like a brother bla bla bla) and that this chick ( Jessica ) is stealing me. Maybe I left out some details, sorry for punctuation and grammar issues.