No desire to comment on the rest of the OP points, but the one about gym was the most baffling one to me. Out of all places I could think of, gym is one of the most accepting places ever for all kinds of people (including extremely obese people).
From my own observations, people at the gym tend to fall in one of the 2 categories: they are either (a) extremely supportive or (b) totally not caring about anything but getting their own workout done and getting out. Of course there could be exceptions, but the only time i've ever even heard of such a thing happening, those types of people usually get shunned by the rest of gym goers for being assholes and ultimately banned from gyms.
In fact, more often than not, when I see a person at the gym who is clearly a very beginner (judging purely by how they are walking around for a while trying to find a specific piece of equipment, regardless of whether they are obese or not), I almost instantly see other gym goers helping them out with minor stuff or cheering them on weeks later once they accomplish a milestone. From my personal experience, the most intimidating-looking fit people at the gym end up being the nicest and most helpful towards beginners.
This sidenote aside, I find it extremely suspicious that the OP just said "It was crystal clear I don't belong" in reference to gym, without any specifics. What made it "clear" to her? The fact that she was looking at other people and realized that a lot of them were a bit further along their journey to being fit? Or did something actually happen that made her feel that way? Because a lot of her other points and complaints seem to have a lot of specifics, but this one has absolutely none.
It is also a bit strange how she is all about utilizing all other benefits and perks provided by the company, as evident by her mentioning tons of specific instances of that (no shame in that, as everyone should feel empowered to take advantage of things offered to them by the employer for free). She even rationalizes a lot of it as something due to her being from a rather poor background, even if she knows she shouldn't utilize those as much (drinking until getting sick, because it is free). But when it comes to the gym membership covered by her employer, she is totally willing to give up this perk, despite it usually being a pretty valuable perk in terms of costs covered.