I'm sorry it was a harrowing experience but glad you came out of it otherwise unscathed. I would have been freaking out just from losing my friends in the crowd. I've lost site momentarily in a large crowd before and felt the panic well up.
Fortunately the crowd wasn't too big... maybe a hundred... a couple hundred people? Not sure. but it was much smaller than the previous ones I'd been to. The miku concert... god, there must've been thousands... I couldn't see anything.