If someone told me I was directionless and uninspired I would just laugh because I know they couldn't be basing it off what they see of me. I've had a very clear direction for a long time. You say ouch though. I think the truth hurts. You are spinning and you need to pick a direction and just aim yourself in it. Think of a job or an area of work you want to head in and work out what the steps are to getting there. That's what CV building is about.
You need an income - find a job that will give you this. If it's one for which you're overqualified and doesn't necessarily use your graduate skills, fair enough. It'll maybe have other benefits to it. I did a stint at the royal mail once that was great because I started at 6 and finished at 2. Gave me a fairly good income and allowed me time in the afternoons and evenings to do volunteering and socialising. I also worked at a care home for a while on the night shift and I learned a huge amount there about the practical application of things I'm interested in, particularly mental health. Because of the flexibility I could get all my hours out of the way in two days of the week and had the opportunity to start building my business around it and doing volunteering around it. Didn't take much to get either one of those jobs but they gave me freedom and time, which I needed.
You need some practical experience in the area related to that which you want to go into. Do-it.org is a great website with thousands of volunteering opportunities available. Getting involved with the BRC is also a good idea as their volunteer training programmes are incredibly diverse. CAB is also a great place to start volunteering as well, particularly if you are interested in working in the public sector in some way. This is why I question you working in a charity shop. Doing retail equips you for just about one thing: retail. It was pretty much a waste of your time CV building wise when you could have been using that time for something that would have given you something significant to add to your CV.
You need to take some time to enjoy yourself and get a social network back. Get involved in a sports centre or anything. Take up a hobby. Anything. The expression get a life is harsh yes, but it's something you need to do if you're going to be happy.
I wasn't specifically referring to getting medical help. There are support groups and phone numbers you could have been calling that would have allowed you to reconnect with people and boost your confidence and prevent you becoming so demoralised. Often they can provide practical skills training as well.
With direction you can start filling in these blanks and achieving some goals. You lack that clearly, otherwise you would have done it some time ago.
Re: getting into teaching, put teach first out of your head for a while. The way you are right now, you wouldn't get through the application process most likely but it is something you can build towards if you're interested in it.
Your attitude is one of woe is me, I deserve better than this. A generalisation but one I've personally had to confront in several people I care about greatly. Yes, the economy was rubbish but there was always an option of work out there. I know someone who lost a graduate job in January '09, spent only 2 weeks on the dole and started scraping. He did home fundraising jobs, spent a couple of weeks trying to flog Sky television on commission only, got a job in sales, slogged that out while he built himself up again, got a job with a bank off the back of it and worked steadily at it for three years. He's now been accepted onto one of the top rated graduate schemes in the country. He accepted what his capabilities were, shouldered responsibility and got on with it. Yes, the economy was rubbish. He was willing to do anything to keep working and keep his CV in good order. He would complain he wasn't being stretched at his job and at times his job would be crippling to his esteem, but he kept going. That resilience has paid off.
Look at what your competition is doing. If they're doing it, you need to do that or better. If someone has an advantage over you, find a way to close it. Just get on with it.