If he asked for a note, then this sounds like something you do a lot. If you don't have a note, depending on how often this has happened, you can be fired. Good Luck
If it happens repeatedly then they may fire you, but if its just a once or twice a year thing then professional bosses know this can happen and that wouldn't be an issue.
They CAN, but probably won't unless you have called off a lot. Explain to the manager what happened.
If you had no transportation, how were you planning to get to work?
No, just tell him he refused to write a docotrs note or just say you forgot. or the truth.