Rebuked At Work For Laziness

[beatitude]

Tonight at my volunteer placement the manager rebuked me (in front of five other employees) for being lazy and told me that I couldn't slack at a busy time. In her position, I wouldn't have said the things she said publicly like that, but it was certainly a justified criticism - I really was slacking today and I knew it. What makes it worse is that I've only been volunteering here for two weeks and I know that bad first impressions are hard to correct. At the end of the evening the other manager said to me, "So, fresh start tomorrow, when you're here you help with everything." I agreed and said sorry, but I hate being criticised for anything - a real weakness of mine - and it's difficult not to obsess about it afterwards and what a lazy weak person I am. Please pray that I will be constructive about this and show the improvements they want, and that this doesn't sour the rest of my placement. Thanks.