Hi everyone, I'm new here and i'm not entirely sure I'm posting in the correct place. But here goes...
My son is a beautiful, bright, funny and amazing person. Everybody has always said, even at a very early age, that he's the nicest and most loving child they've ever encountered. He's always been so grown-up, it's almost scary at times. He's always been so attuned to those around him, like an adult would be. It feels as though he hasn't had much of a childhood because of how he is - something I feel guilty for but at the same time it's been out of my control, it's not as though I can tell him to switch off.
But over the years he's become increasingly shut down, I think i've been in denial about it. I tell him multiple times a day that I love him and i'm here if he wants to talk or do anything, but for some reason he's been so shut off. He acts happy, but I'm not sure if its because i'm his mother and I can see underneath his act but he just seems so unhappy to me even through his often sillyness. I want to connect with him more and I honestly don't know how.
Over the past few months, he's been having headaches and ear issues, he also suffers from "Alice in wonderland syndrome" where he sees everything small quite often which he really doesn't like (and even these things, he won't tell me unless I notice he's struggling and I ask). We were reffered to get him a hearing test which he passed fine, which makes no sense and they said he may be experiencing 'episodes' of hearing loss which may indicate a possible brain problem (possibly the temporal lobe, due to the issues he has. Also they said the fits he had as a newborn may be the culprit. He's been reffered to a neurologist, but we don't know anything yet).

Anyway, this is just a quick background of what's being dealt with in his life right now, although he isn't aware of most of it (being reffered to a neurologist at least).

Now for the sting... about 2 hours ago, he was playing with his little brother and he came over to me and hugged me and told me he feels "blank", I asked what he meant and he said he doesn't know, he just "doesn't feel happy" and he feels "empty". I tried to reassure him that sometimes feeling down was normal and that no matter how he feels, at any point in his life, no matter how bad it is, that feelings can change and get better and feeling down at any point is only temporary... but inside, I was mortified. I still am. I feel like I've failed him on so many levels... how could I not see how bad he was? Is he depressed? What possible reason would he have of being depressed? I have no idea what's happened or what to do or if he's actually depressed or not. I have never ever felt like such a bad mother.
What can I do to help him? Any advice would be much appreciated.

Thank you in advance, and I'm sorry it's so long.
K