Are you posting your fanfiction and your original work in the same place? I do that - because I don't really care about my original work and it's fanfic-ish anyway. And you're right, the same thing happens to me. But the thing is, people on a fanfic site aren't looking to read original work. They're looking to read fanfic.
There are a few writing subreddits. I've gotten good (for me) responses to the few original works I've posted to /r/WritingPrompts. A few upvotes. I posted the same works to my fanfiction account, and not only did I not get many likes/comments, I hardly got any hits. :) The same thing happens when I post fanfic that's in an unpopular category (f/f pairings, m/m pairings with no sex). I know I have some in those categories which are better than others I've gotten more attention for, but people aren't interested in reading those. You're right, they want their lemons. I understand that, but it does get frustrating sometimes to put a lot of effort into something that I feel people would enjoy reading, only to have it be overlooked. But yeah, they're just not looking for what I'm putting out there. I know that doesn't mean it's bad work, necessarily, because I've found lots of wonderful overlooked works by other authors.
I think you just need to find your audience. It sounds like people just aren't even seeing your work. I don't know where people do post original amateur fiction, though, other than Reddit. I've seen some mentions of the site Wattpad, but I don't know what kinds of works are popular there. There are also some communities for original fiction on LiveJournal, or communities for both original work and fanfic, like this one. If you do some searching on LiveJournal, I think you'll find a place where people want to read your stuff. I wish I knew exactly where to point you, though - sorry that I don't!