From what I gathered, to process a bitcoin transaction I basically create the transaction object locally, add my signature generated with my private key, then send this to a public node for it to add it to the next block.

However I do not understand what stops this transaction from being re-used. If I want to make another transfer to the same address for the same amount, it would end up with the same signature? So what stops someone from copying the raw transaction (with my signature) from a past transaction and trying to execute it again? How is bitcoin protected against that?