TEENS: I need help with a certain someone?

So Im kinda new in school and I have this huge crush on this boy for the longest,every since I came to the school which was 3 months ago. I made it very clear that I liked him every time I was near him,and I actually thought that he liked me to. So schoo'sl out for the summer(obviously) and Im in summer school with him,were not together sadly. I really wanted to make him mine, but today we were all in a little group in the hallway just chillin with 2 of my friends and him and his friend. Then all of the suddenly this girl comes over and starts to chill with us,I had no idea who she was but apparently everyone else did. She sat right next to my crush ,than all of the suddenly they start flirting BIG TIME. I was so upset.&then after school she came back to where we were and started to flirt with him again,and what made me made is than he was doing it to.They were hugging eachother,while his hands around her waist. I even saw them holding hands. You don't know how upset I was,of course I didn't show it but I was tearing apart inside. I just put a smile on my face as if I wasn't looking at them. I recently found out that,that was his 2times ex girlfriend,& that they might get back together. do you think I could still have a chance with him?