Thank you both.
lapdog I misunderstood a bit before - when I was wondering about why don't people like us end up bumping into each other IRL... I thought you meant there were a lot of people who want to connect with others and generally to have more community mindedness, not specifically people with mental illness. You are right though, I remember the days I was less shy and it's amazing how many people have these struggles and you just wouldn't know. It's reassuring but sad to know that, isn't it?!
It's interesting what your friend said re. different kinds of illness... I wonder how much is due to the different way it gets treated by others? Eg. Asking for help with shopping was ok when I couldn't physically carry it/walk far, but asking because you feel mentally unable to go to the shop is different. Or feels different, anyway.
Also there's this whole complication with mental health where you're supposed to/expected to push yourself til you can't cope, to sort of 'prove' you're ill. By that I mean supposing someone getting my shopping meant things were that much easier that I could still smile and get other bits done. It would look like I was taking the piss! Whereas with physical health getting help so you don't push too far and end up in pain is generally more accepted. (I stupidly went bumbling off to a friend's (not close but used to be) the day of my laparoscopy, dosed up on codeine, because I could and forgot to think whether walking etc was a good idea! Paid for it!)
There's also the way people treat each other. This is difficult to explain... erm... as an example: Growing up I was told/shown I was 'crying too much' 'overreacting', needing to try harder, wrong for struggling with doing things etc. Then, as I grew up, I heard of 'depression' and 'suicide' and 'mental illness'. I found it so odd that I was a rubbish failure outcast according to one view, then once you bung the label of 'depression' on it's suddenly "Ooh, we must be kind and supportive to these people". But if that kindness and supportiveness had been there all along then quite likely I'd have not ever become unhappy enough to aquire the label. But without the label, no empathy. Argh I'm getting unstuck trying to work out wht I'm trying to say here!
IceBeing Actually people do look out for each other, and suddenly descending into incoherent babble is something that people will take for what it is - a sign that you need help and are having a serious problem.
Ah, yes, random strangers do, of course. Mental health bods like to go with "attention-seeking" or sigh loudly to show what martyrs they are for dealing with people like me. They also get cross and won't speak to me if I'm "not making sense". They take advantage of the confusion to end the appointment/assessment and bugger off, if in person, or if over the phone then tell me to phone back when calm. Not all of them, but it's not worth the risk when it could tip me over into doing something awful.
People you know in person - when aforementioned mental health bod hasn't managed to take them aside, breeched confidentiality, and told them stuff that makes them hate you - tend to not believe your problems if MH services aren't taking you seriously. It also freaks them right out when services try to palm off responsibilty onto them, or if they realise that no, services aren't going to help, so suddenly knowing you is harder. Which is a massive shame because even in the most dire mental health crisis, all I've needed is someone to talk to, to have a hug and a cup of tea and eventually a giggle. Even if things are really bad a daily dose of this will help me pull through. I don't expect anyone to make it better, but I think people find it hard to let mental illness be there, at all, and be supportive - they seem to expect to make it all disappear, and if they can't, withdraw completely.
Obvs. feeling a bit better as have written an essay 
oops!