My ex broke up with me. im ok having her around but the way she acts is like she really hates me. and i dont k?

we were going out for 6 months. and after our exams she said that she said that she didnt feel the same and that she didnt love me anymore so she broke up with me. 2 weeks later we are ona field course and she is acting really bitchy towards me and is making me look a fool in front of my friends. i did nothing wrong to her and i dont know why shes acting like this