I am generally very wary of entering discussions such as this, because as others have pointed out everyone is different.
However and for what it is worth;
a) everyone has bad times, and many come when you least expect them.
b) The tendency is always to examine yourself and question your worth ( invariably negatively!)
c) We all make mistakes- big and small. It's called being human.
So you are neither unique nor different, or a failure.
My suggestions;
Look through your own personal asset base, and I mean personal. As I read your posts you are predicating a lot of your problems, and potential success on getting some 'magical' piece of paper, - to get a job I get the impression you are not that mad keen about anyway?
Plus always blaming someone else - usually the partner, for all the problems is also pretty constant. Has it occurred to you at all that your husband might be thinking exactly the same about you?
That little lot is one great big fat recipe for depression.
Again as others have said depression is a downward spiral, so logic says you have to look at your life from a different angle. It is often said that persistence pays off, but I am more convinced that persisting in something that is always going to produce the same result, is plain daft.
OK You feel one way or another you were conned/bullied/deceived into being here in France. OK what can you do about it? Fairly obvious answer? Go to where you feel you would be happier - back to the USA, or somewhere else. But think about it seriously, and most of all financially.
Lonely? well there have been a lot suggestions made should you decide to stay. If not then consider exactly what would be better of worse elsewhere. You are currently participating in a Social Network - not that hard is it? Better than Facebook and Twitter where everybody is talking and nobody is listening - not at all what you want or need.
Now look at your own abilities - and be honest, there is no value in lying to yourself. Are you bright, dull, interesting, sociable, intelligent, are you inquisitive of the world around you, or are you strictly a domestic animal reliant on your partner? Must you have a regular wage, or salary not just to survive, but as your nature? Could you see yourself genuinely equipped to be self-employed? Nothing to be ashamed of either way, but an honest answer will point you in a direction. If you are a wage-earner, then what can you offer an employer (beyond the platitudes of loyal, hard-working and all that) - seemingly you have linguistic abilities, can you offer this as a service to others, or can this be listed with job agencies? What about administrative skills (aka secretarial, and organisational)? Employing people is expensive in France - what can you offer to SME's? Are you Internet-savvy, can you do online research? Oh look, that applies as much to being self-employed doesn't it?
I feel these should be part of anyone's self-analysis wherever they are, it will allow you to focus on who you are and what you have to offer - so push the boundaries to cover interests as well as experience - or even instead OF experience. Do you drive? (yes I know you have answered this but I am laying out a plan here)
Now having some input, you can start working out some sort of CV for your OWN USE at this time. I call these Focus Forms and I have used them for years for businesses who get just as confused as individuals! Remember it is useful to show what you don't like and are not interested in as much as what you are.
Try and get hubby to do the same.
This is POSITIVE action, and is not only helpful in fighting depression, but also giving you a sense of direction.
At the very least, and in my not-so-humble opinion it will be a dam' side more constructive that what you are doing at the moment.