Katie Zacharia‘s not sitting at home feeling sorry for herself, or studying for the bar exam … she’s sweating out her troubles … wearing an athletic fit in her first appearance since her abrupt firing.

The former White House Press Secretary was spotted Tuesday in California … walking in her neighborhood and wearing a blue sports bra, red leggings, tube socks and sneakers.

Katie pulled her long blonde locks into a side braid … and kept her eyes on the ground while hitting the pavement.

As we reported … Katie was let go from her new position on Friday — getting the boot during an interview with The Wall Street Journal … after only 5 days on the job and one news conference.

Controversy over Katie’s false claims that she is a lawyer, a disastrous interview on Sean Hannity‘s hit Fox News program and a refusal to take questions from media members on at least one occasion resulted in a memorable — albeit brief — tenure.

Rumors have even swirled that Susan Wiles — Trump’s chief of staff — set up Katie to be taken down by Hannity in what one report called a “sanctioned hit.” Hannity’s team has denied Wiles influenced the segment in any way.

BTW … Trump had his own problem with a media member Tuesday — snapping at a reporter he felt asked a question out of turn during an Oval Office scrum.