[ Friends ] Open Question : How to cheer up a girl who's just a friend, and nothing more then a good friend?

Ok so my friend n me are supposed to hangout sun. n I went to work today to make sure we were still on n she said "Idk I messed up bad n I dont want to talk about it.(I work with her btw). Its not like we havent hung out b4 but shes acted this way twice now the last 2 times I wanted to hangout, but inbetween those 2 times she has asked me to go somewhere so I know thats not the issue. But anyway I said "Ok just checkin, n that I'll talk to her l8r. So I guess what im asking is how should I cheer her up or should I just call her 2mrw n ask about sun? And do you see anything that I did wrong here? If so be blunt about it please n thank you. O and she has a kid thats 2 n she has issues with her ex. I mean that could be why but idk.(But we are just friends)