I feel sick I’m being ghosted

i was talking to this guy for a week and I was starting to like him and the whole time it was being reciprocated. He kept suggesting we do things together, we meet up, sending like flirty texts and emojis and now I haven’t heard back from him. I don’t know what changed. The last text he sent me was affectionate and now he hasn’t responded to my text and it’s been 10 hours. What could have changed