Yes I can relate. I almost broke up recently because I found myself depressed and fed up, and I couldn't bare to give attention to my relationship. I felt almost overwhelmed, because she loves me a lot and wants to see me a lot.
I felt like this mostly because being so frustrated with my life. Also because I feel like she is experiencing some of the same troubles in life (but seems to rely on my love to feel better, instead of trying to actively improve things in her life. She seems to have low self-worth and I feel like she leans on me too much instead of trying to deal with her problems herself. ) and I thought in my negative down moment that we needed to resolve our issues seperately, and break up.
To be honest there were a few other things in our relationship that were going awry, such as not being a very mature relationship (hardly any communication) playing nice weather all the time, not talking about our problems. But we had a talk that night, that made me positive that we can be able to communicate better and try to improve on herself as a pro-active person as well. I think we took a step into the right direction, and I am glad the pressure's off the kettle, but it was very close to breaking up. I'm glad she understood the problems, and recognized them as well, whereas I thought it was hopeless.
As far as me being paranoid about her relatives thinking things of me, yes I have the same issues, mostly because of some important problem, I don't speak their language. (yay me for getting myself in these situations with my already existing SA) That makes me feel like I'm being talked about, or the third quiet wheel all the time. The French are also always reluctant to speak English in my experience, though not all of them. But oh well, I feel if the relationship is good and strong enough, that doesn't matter so much and I can learn the language. If I ever get around to :

:.
I can totally relate to your thoughts. You feel like people are taking the pi$$ out of you, that is an awful feeling that I've had many times. People act like you're slow, or "special", you feel like they're winking to each other behind your back, or they try to be extra nice to you in a sort of embarrassing way, like you're, pardon my French, retarded. I can say that most of the times, these things aren't true and exist only in your mind. But if they are true, try to not be as intimidated by it. Who cares what they think of me, it's not the end of the world, etc.
I would also suggest to you that you tell your husband about your feelings during these social gatherings, and be more communicative with him if you weren't already. Honesty and openness is very crucial to a relationship.