I remain high functioning whether I'm in an upswing or a downswing. Although I'm less likely to do certain things when I'm depressed and more likely to do other things when I'm "up" unless a person knows me well, they likely won't recognize that something is wrong. And even the ones who are close to me often chalk it up to my oddities and write it off as some variation of "normal." A few days ago, I tried to talk to a family member about the stress that I was going through at work and how I felt that it might tip me over the edge if I'm not careful. They shrugged and waved it off as an overexaggeration. In the next breath, they encouraged me to accept even more responsibilities at work.
Family and friends aren't always the best people to go to when we're suffering. I'm sorry that you're experiencing that.