07/19/22 Helping Workplace

Yesterday I got a text from my boss that she needed me to come in early. The shift hours were 12pm to 8pm. I normally work 3pm to 10pm. I said yes cuz it’s rare that they ask me this. I was having a lot anxiety and kept playing situations in my head. I was anxious my whole shift and I felt completely exhausted. Just not long ago. She sent me a text saying she got coverage for today and tomorrow. But needs some one Friday. I automatically sent her a text saying I have a car appointment. Which is a completely. But I just got a huge relief after I sent my text. Has anyone done this? Lie to there boss because you have bad anxiety and your not good with change?