Depression can be very isolating. I often feel rather " detached " and isolated from other people, who sometimes seem to be able not to be affected by things that trouble me. And, if I am isolated from people for too long, that can also be a trigger for my depression and anxiety.
But, one thing that I am now SURE of, is that there are a lot of people in the same boat as we are.
My GP ( General Practitioner, a doctor in general practice, for our U.S. cousins!

), told me that she would estimate that sometimes as much as about 40% of her caseload is related in some form to depression. This includes not only people diagnosed with depression/anxiety/etc, but also people whose illnesses may be rooted in, or worsened by, undiagnosed depression that they feel unable or unwilling to talk about. Eg. People who are drinking too much, smoking too much, or eating unhealthily, or suffering from some other manifestation of an undiagnosed depression that they feel unable to admit to or talk about directly.
Who knows? Add all the depressives, etc together and we might even outnumber the " normal " people!

( Although, I don't know many " normal " people, so I couldn't say for sure!

)