Little Neo,
Congrats on your 1st play out in public. As for the foot tapping, since you are comfortable dancing, you might try feeling the beat in the core of your body. I feel it in my hips usually. Often if I'm having trouble staying with the beat on a song I'm singing, I have to move to the music. It's almost like the foot is too far removed from my brain. I have to have a closer connect. I also find it easier to lift my heel to the beat rather than tapping my toe. Maybe that has something to do with the muscles in my calves.
I saw a Breton band play last year and their feet were all over the place. Often it looked as though they were dancing. Fun to watch. I'm sure they didn't even realize it was happening.
Good luck. Just feel it, don't think it.
Emily