Is it legal as an at will employee to be fired after being in a car accident on the way to work?

Upon returning to work to soon one day after the car accident, I checked my email and the new manager sent me 2 emails that demanded for me to contact her an not a coworker for any reason for not being able to show for work. The time of the email was the same day and time of the accident. She followed with other emails listing unrealistic expectations in a very hostile manner during the time I needed to be out recovering from the accident.