Not sure what to do about my best friend :S

Okay so recently I've started to find that I can't stand being around my best friend of 4 years, and that she really irritates me whenever I'm around her. At first I didn't really know why that was the case but just last week we went on a five day holiday with my brother, his girlfriend and his best friend. The whole time she kept making inappropriate, offensive and undermining comments that just irritated everyone, including me. Like while we were travelling home we had a few hour break in London and we went to a food court to get some dinner before the long coach back home. She went to the toilet and found out you had to pay, but she has a medical emergency card that she is supposed to use to gain access to disabled toilets. Anyway she showed it to the attendant but the attendant didn't know what it was. She stormed back out to where I was sat and complained about how the attendant clearly couldn't understand English as she didn't know what the card was for. The thing was that mostly of the staff (cleaners, toilet attendants, etc.) were black, and I could tell that she was assuming that just because the attendant didn't know what the card was and the coincidence that she was black, that she was an immigrant worker who didn't speak English. Or on the coach she said how she had accidentally run a few 'Asians' over with suitcase trying to get on which I found offensive because she didn't really need to distinguish the fact that they were Chinese or 'Asians' but she did, making the whole comment just plain racist.

It's not only racist comments she makes. She also makes homophobic comments (mostly about how all gay people do is have bum sex) about our other friend who defines himself as being pan-sexual, even though she think's they are just innocent jokes and she isn't actually homophobic. Besides that she makes really undermining and inappropriate comments to me. Like she will say that my illness (I have IBS) isn't anything compared to her illness (she has Crohn's disease), and acts like I have no right to complain about how much pain my illness causes me on a daily basis because of how much pain she went through with her illness. It makes me feel really upset and unsupported because I go through a lot of pain with my IBS and there isn't any treatment for it (there isn't a cure) and instead of acknowledging that and supporting me she just undermines it because she's so wrapped up in her own problems that she thinks nobody else can have any of their own. She also regularly makes comments about my height and body shape that I find inappropriate, mostly to do with my breasts being large and how I should 'show them off' because then I'd 'easily get a boyfriend'. I get really upset and irritated by this because I only recently got into recovery from eating disorder, plus I've previously been victim of attempted rape from which I suffer from post traumatic stress disorder. She knows about both of these things and I explain recently how these comments make me feel, but she seems to just ignore it and not care because she keeps saying these things.

I don't know what to do because I don't want to be around her the way she's behaving. I also don't feel it's healthy for my recovery from eating disorder and PTSD for me to be around her the way she is. Yet I don't want to hurt her by breaking off our friendship and losing my best friend.

Anyone got any advice? Should I break off from her?

Note: sorry for how long this post is, it's kinda been a big issue