I just happened to notice your thread, and I don't know your history as others seem to do, but I just wanted to say that whilst sometimes it can be nice to have people trying to help you out with specific problems, even though it's well-intentioned, sometimes it is done without too much knowledge of the situation. For example, the library job that was posted by someone further up saying "here you go, what about this". It caught my eye because I have a degree in information & library management so have much experience in libraries and the interviewing process. Unless you have experience in a library or a library qualification, then you would be unlikely to get an interview for that. There is actually a lot of competition for jobs in libraries believe it or not! So it is unrealistic for people to post suggestions of jobs unless they have some knowledge of the field it's in, no matter how low-level the job appears to be to outsiders.
It can also be a bit of a vicious circle regarding positions that need NVQs. To get the NVQ in the first place, you need to be in a placement, and they are not that easy to arrange sometimes for various reasons, even for someone who doesn't have the problems the OP has. You DO have to keep pounding away at these things, but it doesn't really help when people post with things like "Well, just get the NVQ then" as if it's just a walk in the park.
Personally, without knowing any details, what I would suggest is that if you feel your options are limited by only having 2 GCSEs grade C+, then take babysteps and maybe focus on just doing 1 or 2 GCSEs in college FIRST to get your basic qualification level up. It would also improve your self-esteem and social life a bit too. Who knows, you may even meet a nice fella?
It can be hard sometimes to point out to people why something they suggest is legitimately not for you due to whatever reason without coming across as negative. Some people are naturally more optimistic and would apply for job after job when someone who is more of a realist would know that they wouldn't stand a chance of getting an interview, never mind the job, so would save themselves the effort of doing all the forms etc.
I think the key, as somone said, is to find something that YOU want to do, as long as it is doable, even if it means you have to do it in little steps to get the end result. And be realistic but not pessimistic.
anyway, I might be talking about my arse so I'll stop there.