Yo, this feeling has been so pervasive that I'm like writing a comic right now just about this same feeling because it's been everywhere I've gone lately, comics or not. I think it helps me that comics aren't my endgame, but just a thing that I do--I actually would rather end up in doing covers or concept art, and the medium I tell my stories is relatively unimportant to me, so long as I can keep telling stories.
But, that doesn't mean I'm in any way immune to that feeling of loss and rejection when it inevitably comes. I think it's OK to grieve if a story's expectation's aren't met, and that it's OK to walk away and do something else for a while. In fact, I think that time is really helpful for putting things in perspective. We have a lot of life to live and a lot of stories to tell.
These websites come and go in an instant, followers come and go, but your art is forever and in the end no one will know or care how many notes it got. Like, for instance, all my old art I put on my old LJ was hosted through an image site that died, so all art I posted before 2005 is a broken link. I also had like 3 blogs on blogger--and blogger died in the mid 10's so now I can't easily access any of them: none of those posts, none of that art. So, what I own from that era is what is on my own computer and I honestly don't remember anymore which was popular or not. It doesn't matter anymore. But, I'm glad I made the art.