Firstly I don't think you expressed it badly, I think you expressed it and people misunderstood you - which is very easy to do unfortunately.
I feel intimidated by those who are high functioning and disappointed that I'm not. I also feel that this invalidates me - but not because of their actions or words, but because I use there ability as a bar to which I should be able to reach, because I'm not it hits me like a punch in the stomach.
For me I know that this isn't the case. Retrospectively I know that had PTSD from about the age of 10, I had somatic pains to deal with as well all the many psychological issues. From the age of about 3, my nan (who was very involved in my upbringing) used to tell me I was stupid and pathetic because I was lactose intolerant and later on (5) that I needed my tonsils removed - I was always ill, I was told because my father was of a poor background, of bad genetic quality and as such, and as an illegitimate child, I was a disgrace (though my sisters, from the same father was not). When I got bullied (death threats and daily beatings, not just name calling) she seemed to think that was good for me.
After I started suffering visibly, she said I was making it up, my mum was confused - I had so many problems, so much of the time. My doctors treated me with scepticism but over the years I had many blood tests and other check ups - all with no results. I ended up in hospital under observation for extreme stomach pains - I was given an ultrasound which showed irregularities, but when asked if I had had sex I vehemently denied it (and so did my mum, I never went out, I was socially deficient), I didn't tell the hospital staff but I had extreme vaginal bleeding I had a very early miscarriage - from the abuse I was scared to tell of - so again I was mislabelled as a faker and an attention seeker. After that I was misdiagnosed and ignored by the child psychologists/psychiatrists I saw, outcast by the teachers at my school, the few friends I had and the worst straw for me - completely disbelieved by my mum.
I don't function well, I have no social life, no job and can't live on my own (I've done it but not well), I can't seem to do anything others can - I thought that was PTSD and the other disorders I have, but when I hear of others doing well with PTSD, it's apparent it's just me. Sometimes I can pretend to for a few days or a week or so, but then it takes me quite literally several years to recover from it and I can't understand why. The last bout I never recovered from and then my PTSD exploded worse than ever before. When I see or hear of others functioning well, I feel as if I'm being told I'm deficient, I'm not worthy, I'm useless and a waste of space - I know I'm not, I know it's projection, but I still feel that way. Even if it's observed from a long distance or the well-functioning people don't even know of my existence, my seeing or hearing, or how much it affects me.
So I can't understand how people with PTSD can hold down a job, have a relationship or friends, how they can live on their own. And them doing so well does feel like they're bragging (though they aren't) or that they're thinking "I've overcome it, why can't you?!?" but for me I know it's a case of me thinking "They've overcome it, why can't you?!?". I feel that they're judging me when really I'm judging myself. So I do know what you feel in my own way - I don't presume it's the exact same, but I do understand the principle. **Sigh**, that doesn't really help the problem, but at least I understand what you mean and how it feels (on some level).