Nobody knows how long the stress test will take. It's not an official test, it's just somebody spamming the network in order to slow everybody down. Probably because of some bitcoin politics (somebody that wants to push for a block size increase, or wants to push for higher fees).

The network won't rebroadcast it, either you have to rebroadcast it yourself (your wallet might take care of this, depending on which walled you used), ask somebody to rebroadcast it for you (Shorena might be able to help you), or the funds will return to your wallet after a couple of days (or your transaction might be confirmed by then)

No worries. We are having some stress tests at the moment, which is a rather frequent exercise for the network. Your transaction should eventually get confirmed.

However, if it fails to confirm it will return to the sender, so please keep your private key/wallet access of the sending source...