Is she purposely doing this to me?

from what you sed, it sounds like she didnt use to answer that way, like all happy and stuff.... so now, she's either answering like that because she's much better off or because she's really not happy but she doesnt wanna show anything and she's pretending everythings fine..... i think she's acting overly cheerful on purpose, i know i would do the same thing if my ex texted me and i still liked him.... i would say just be straight up and ask her if she misses you, you'll never find out otherwise......im almost sure her answer will be yes..... good luck!!!!!!! :)