what should i do?

So i got turned down by this girl that i liked ....she going back to her place far away I I probably won't see her anymore....but I have this sick,uneasy feeling that I still want to talk to her she is very nice and she rejected me very nicely she even thanked me for asking her out(she got a boyfriend)....when I see her I still say hi and I'm okay on the outside but on the inside I'm frustrated and forcing myself to become happy.......

should i just forget about her or talk to her one last time?