You need to check your local labor laws because the answer depends heavily on where you live and what your actual job duties are. In the US, salaried employees are often exempt from overtime pay if they meet certain criteria (usually making above a threshold and doing management/professional work), but some states have stricter rules, and some jobs don't qualify for exemption no matter the salary. If you're genuinely exhausted and this has been going on for months, it's worth documenting your hours and either talking to HR about it or consulting with a labor attorney or your state's labor board to understand what you're actually entitled to - your manager saying "it's just part of the job" doesn't automatically make unpaid overtime legal.