I think it's very common to feel alone during depression, people that haven't been there don't understand, get scared by it, don't know what to say. The social stigma still surrounding any sort of MH issue makes us feel awkward talking about it.
Then the illness itself saps our confidence, makes everything so much effort.
Im right there with you... The more people there are around me, the more lonely I feel. Everything is so difficult.. Just getting through the day is like a huge lonely mission. So you're no alone in feeling alone... We probably all do at times x