This is one of the most heart warming and wonderful threads I've read on here in recent times. Really reminds me what I love so much about geoexpat and how grateful I am (and I'm sure most members are) of how positive and useful a resource this is.
Dear OP - If it wasn't already clear from the majority of the generous posters so far... Don't lose heart, you'll be ok, and the way to pick things up won't be as hard as it feels like will be at the moment! Don't worry too much about how any of these initial steps will solve your plethora (and you do have a few!) of gripes about Hong Kong, just have faith that the problem doesn't really lie within those superficial issues. When you find something that reignites you as a person and gets you out of bed in the morning, very quickly you'll start seeing everything else falls into place and dare I say, what was once an annoyance will turn into a novelty and quirk of this truly unique place.
Hong Kong is a wonderfully vibrant and friendly place on many levels and you don't necessarily need to be the world's most social type A extrovert to tap into it and to find your own place and connections with it. Expats here are generally very open and welcoming (so long as you also make the conscious choice to be so too), and people are just so much more up for meeting up and networking spontaneously than in many other capital cities in the world.
Your first attempt to reach out may not yield the life changing results you'd hope but that's ok, you just try again with yet another activity, group, or meetup that has something in it that you're excited about ("are there any childless housewives", and "will this group help me feel more at home in HK" are NOT valid criteria for picking what to join / do!). If nothing happens, hell who cares, you still had a good time doing stuff you like. And sooner or later, you'll get into your groove and find that the handful of good supportive friends you've made are not necessarily childless housewives, but maybe crochet-knitting heavy metal Buddhists whom you never ever thought you'd befriend!
Finally, I wanted to raise a thought for you to consider that still amazes me every day I'm here. There are some people with many of life's comforts and perhaps even great wealth, who can still be deeply unhappy with their situation and life here, yet there are also some people who have so little and live in such cramped conditions here yet have so much joy and contentment in comparison. I'm not judging you or your situation, nor suggesting that wealth is a bad thing (and well done if you've managed to achieve great things in this respect), but I guess what I am saying is that it's worth considering how some of these comforts and capabilities can in fact be a barrier to ones own situation (and happiness) especially in a city like Hong Kong that has such an obsession with money and all things it can buy - it's all too easy (and understandable when one does) to get lost in the fickleness of this when the cues are all around us, in this relatively tiny and cramped, but at the same time, full of life and unique place.
Good luck, and you'll be fine