Really want to know If I am cheated…

My ex girlfriend, who broke up with me telling me that she suffered from heavy work, and therefore cannot continue this relationship. But now I notice that her WeChat background has changed to another man’s hand with a cat…

Am I actually cheated and she made up those lies to drive me away…

I don’t want to be like I do not sympathize with her situation, but she broke up with me by just texting and all those happened within half an hour… I requested that maybe give me like half a month to prepare myself because this is a great shock for me, and she refused coldly saying that I am the selfish one… All these things happened just one and a half month ago.

So anyone can tell me if I overthink too much or it is more likely I am cheated…