Your manager knows you're drowning. You've just gotten too good at drowning quietly.

Your manager probably knows you’re overwhelmed. The problem is that most managers don’t measure stress. They measure outcomes. If you keep absorbing extra work, working late, and somehow getting everything done, you’re unintentionally teaching people that your workload is manageable. Instead of saying “I’m overwhelmed,” try forcing prioritization: “Given current capacity, completing Project A means Project B will be delayed. Which would you like me to prioritize?” Stop proving how much you can handle. You are signalling that your workload is manageable. The problem isn't urgent unless you're actually missing deliverables. So every time you absorb another project, you work late to get something done, you quietly figure stuff out. You're proving that you can take on more. Start aggressively prioritizing things.