You said it was a mistake even though you're developing feelings for him? That was a mistake.
If you want things to go anywhere you shouldn't lie about your feelings to him. It sounds like he does actually have feelings for you and when you shut him down like that you destroy his confidence to ask you for anything further. I believe that he does have feelings for you so you either tell him how you feel, or wait for something to happen. Waiting is a giant waste of time and nothing ever happens so I don't recommend doing that.
You could just get drunk with him again and tell him drunk and sleep together again. Then in the morning you can say what you really feel when it will be more natural to do so haha. That's not the best way to do things but it would work.
Cheers
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