Feeling heaviness, apathy, and a loss of interest in life are manifestations of human vulnerability, not failure. Strong people also cry, struggle to get out of bed, and lose motivation. The difference is that strong people seek ways to cope, aren't afraid to ask for help, and learn to let go of what's weighing them down.
Depression is a signal. A signal that you need to take care of yourself, understand your boundaries, talk about your feelings, and seek support. It's not weakness; it's a human experience that requires courage.
And perhaps the strong are strong precisely because they can acknowledge their vulnerability and move on.