Dreams are very specific to the dreamer. (Don’t believe those books that suggest that there are symbols that mean the same thing for everyone.) Without knowing you, all I can do is make an educated guess from the information you provided.
Your dream sounds like an anxiety dream. A number of people have been fired and you don’t get along with the boss. As much as you think you’re handling it well, there is a part of you that worries that you could also be let go. That probably triggered uncomfortable memories of times you were asked to stand up in front of the class when you were a student. Most kids are anxious in those circumstances, so it’s nothing to be ashamed of. The feelings of anxiety triggered thoughts about something else that makes you anxious — the size of your penis and maybe worries about whether you are man enough to manage your job. Each scene in the dream is united by the feelings of anxiety.
If I’m correct, then you may be preparing yourself to handle being laid off, or you may be thinking you need to do something to man-up and take care of yourself. That could mean doing better at work or looking for another job.
That’s the best I can do with limited information. I hope it is helpful.
I wish you well.