best friend drama...

I have been best friends with this girl for about 4 years now. we hang out every weekend, talk about everything, and do plays together. lately, however, things have changed. she doesn't reply to my texts, and when I ask her about them she says she "didn't get them", or whatever. we have this guy friend that we hang out with, her other best friend, who she dated for 6 months, and was still "with" for awhile there after. now they're broken up and he's gay, but he supposedly still loves her. now, they spend every waking minute together, and I'm not exaggerating. he picks her up for school every morning, and he drives her around after school to places like McDonalds, her house, his house, play practice, her family gatherings, his family gatherings, anything, you name it, they probably do it together. and after they finally call it quits, around 11 every night (on the nights they actually go back to their own houses and not both to one of theirs).. I never even see them apart. and let's factor in this other guy, Silas. I've liked him for longer than I've even been friends with her, I'm pretty sure. him and her are best friends as well. they don't spend as much time together as her and her other guy friend, but they text like 24/7. and this is coming from the girl who never gets my goddamned texts. and whenever I try to talk about my own problems, she moves the problem over to her. "hey I'm upset about what happened with Silas." "at least a gay guy doesn't like you." or "hey I'm not feeling well I don't think I can sing for my part in the play tonight" "oh at least you're not sick AND a lead role, like me" like she wants fucking sympathy because she can get a guy to like her and get a bigger role than me. so finally, this past week, I was sick all week with bronchitis. I texted her and asked her to get me my homework and to have her and her friend bring it to me the next day (she's in all of my classes), and no reply. so I went to bed, whatever, and woke up in the middle of the night. like I usually do, I got on Facebook to just see what wAs going on in the world at midnight on a school night for most people. (note: Silas had pneumonia this week too.) and I see she posted on silas's wall. "do you want chicken noodle or Mac and cheese? if you don't reply I'm bringing both." so shell bring the guy I LIKE soup but she won't bring me my fucking homework? or even text and ask how I'm feeling? like really. so finally, I'm really pissed off about the whole thing. she's better than me at everything, and she knows it, but to sit thre and be bff's with Silas when she knows I'd die to get closer to him? the only advice I need is to know if I'm overreacting or not, and what should I do about all of this? sorry it took so long to explain it all :/ I really miss the best friend I used to have, and I want her back, but if I can't get her back, I have no one, really...