My immediate family has been somewhat supportive (my father the most, then my nearly-vegan sister who understands that I'm trying to cure myself of something that held me back a year in school and kept me from having a social life for 4 years, then my mother who rolled her eyes at me when I said I was doing it, but doesn't really care and so far hasn't been given me problems for it), but I don't think any of them actually believe that anything I'm avoiding is bad for me. It doesn't help that I'm not well-spoken in person, so I stay quiet because I can't explain myself very well and have trouble articulating the science behind it all when I'm feeling flustered.
This wasn't a problem until a few days ago, which was the last day of my sister visiting for winter break. We all went out to eat to a nice Italian restaurant, and I ordered the veal meatballs. Rookie mistake: I didn't remember that breadcrumbs are used in meatballs until after I'd finished. I casually mentioned this to my family, and they said, "You'll live." I said, "Yeah, I just won't feel well later." This raised a lot of protest, with my sister saying, "No you won't; it's not like when you eat meat," meaning that when she, being vegetarian/vegan for several years, tries to eat meat (for whatever reason...) she gets a stomach ache. My immediate thought was, "Yes it is." But I didn't say anything because I was so taken aback by the arrogance with which she said it that I knew I would fumble over my words. I let it go, and lo-and-behold had rather gross gastrointestinal issues that night. My parents apologized for not believing me, but my sister told me that it was all in my head. It's stuff like that, besides the "cavewoman" jaunts, that are exasperatingly annoying.