Unfortunately, managers have the tendency give biased one-sided feedback. If you try to ask questions or share your side of the story, you are likely to be told off as "unGoogley" or reprimanded for justifying yourself. Many managers like to dish out work without prioritizing the important ones. If you try to voice up that you are maxed out, you are likely to be given pretty personal and demotivating feedback comparing you with some other colleague, even though the settings are different.