Don’t understand why this would happen?

Went on a date. Went well. Great convos, flirting, he kept touching me, moments of intense eye contact, he complimented me, chemistry and he asked me on a future date to museum we both loved. Then ghosted, didn’t reply for my message for 3 weeks after date :( came back again and apologised but said he’s ‘not in a good headspace right now.’

I’m a bit gutted and don’t know what I did wrong