Return her greetings only. You described a dangerous person. Beware.

And she might have very broad emotional swings. She might grow out of it.

Keep in mind that she, as many people do, might remember dreams as reality.

And you are not alone in being around people who behave in the manner you described.

Start with this: [vimeo.com]

Sounds like she may not be comfortable having her guy friends meet her boyfriend. That can be awkward and especially in a new relationship for someone that may be a little anti-social.

I wouldn't sweat it too much. Friends will come and go in life. All you can do is try your best to be there for them when they need.

Uh also you should probably be honest if you are having more than "friends" feelings about them. Just be completely honest because there really isn't anyway to know how anything will ever work out. People are all crazy and unpredictable in our own ways so best to just be your true self and then you can easily live with no regret. (Working on this myself...not the honesty part but the letting people fade in and out of my life)

Just ignore her.

Maybe she's just socially awkward. I know there have been times when I find that I don't really know what to do with myself, and others when I've been more enthusiastic than a kid in a candy store. Jumping to conclusions can leave you without a ledge to land on. If you need to clarify anything, just ask her. "Hey, I don't mean to be weird or anything, but I noticed your reaction to me on suchandsuch day. Just wanted to make sure we're cool..." She might end up having an explanation that's completely different than anything you assumed. Honest, straightforward conversation beats guessing any day of the week.

Or maybe her vision isn't so good. Or her mind was wandering. Plenty of times I've seen friends or acquaintances but it's too late for me to wave back after I realize who it is, either because I don't see them well, or because I'm off in never never land.
Maybe her new boyfriend is a jealous jerk. Maybe he's not new, but rather rekindled from a failed past relationship.
There are way too many maybes to jump to conclusions.

If you have actually talked with her before, why don't you just ask her?

Some(not all),want to be fought for,an importance in their relationship,maybe she wanted you and the new boyfriend to get into a scufffle,exchange blows,maybe a bloody nose or bruisings?