My job both accepted and declined me

So there was two positions and I bid on both of them, then when I was emailed for both, that job 1 I had to accept or decline. But for job 2 that I wasn’t the most senior person applying. Ok all good so I know should have accepted both but I didn’t, all this happened on April 2.

Only today I got a response back from job 1 clearly stating that I accepted it and to email back the start date for the managers. Only for a couple minutes later that they had gotten it wrong and that there was an error :/. I don’t know what to do, I called my union but left a voicemail and what sucks is I had a shift for tomorrow, that I need to go into like nothing happened today.

Just right now I feel so sad and angry. Even before this they had just closed vacation period before sending out the accept or decline on purpose I think. At least I can hopefully be casual.

Forgot to mention I emailed back the job 2 asking if I could still apply since I was under the impression that I was top candidate.

Any advice right now would be great!, and hope ur day is going well.