Joe90, The people were probably looking at you to see your reactions and wondering if you were in any way involved with her problems. From your reaction, I suppose they'll have worked out that it wasn't anything to do with you. I imagine they thought she was the one acting strangley and you were the 'innocent' party (not that you were being attacked or anything). Maybe they were concerned for you, as they'd probably be ambarrassed too, in a situation like that. Don't worry about it at all.
A couple of years ago, I was in the cafe at our town hall with a friend (no longer a friend, long story, another thread). She was speaking quite loudly, not shouting, but the cafe has a very high ceiling and voices echo. Remembering the types of conversations she started, it's possible that she was saying stuff that people don't normally talk about in public. A man and woman were looking directly at me, laughing and kind of making faces and rolling their eyes. I've no idea who they were. I'm sure now that they were laughing at the loud voice and possibly the topic and me having to put up with it. But, at the time, I wasn't sure why they were acting like that, although I assumed it was something about her. I thought maybe they'd seen her before. Knowing what I know now about her, maybe they'd witnessed her behaviour in the past. But, at the time, she was my friend and I was slightly offended that they were poking fun at her (behind her back) and involving me in the process. They were around 50 and looked kind of professional, so this was really odd, I thought.
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"We act as though comfort and luxury were the chief requirements of life, when all we need to make us really happy is something to be enthusiatic about." Charles Kingsley