How can I tell whether I am experiencing burnout, depression, grief, or simply an exhausting phase of life?

Why do parents sometimes avoid having "awkward" conversations with their kids, and how can this impact their kids' perceptions?
Is it common for students to regret double majoring in physics and math, or do most find it valuable despite the extra effort?
Is it true that working long hours can lead to relationship issues, or is that just an excuse people use for cheating?