If you hold your own coins, that is, if you are the only one in control of your private keys (local Bitcoin node/client), then nothing has happened: you're on both chains. And as long as you don't perform any transactions, that remains the case.
The moment you spend an output, that output (along with possible change that you get back), gets pegged to one of the chains forever.
I'd say: wait for it to stabilize, then choose what client to use from then on.