What best friends?

Recently it's felt as if my best friends of almost 10 years couldn't care less about me, my best friend Alicia in particular. We used to text every single day, all day, and we'd talk on the phone pretty frequently too, but now she never texts me first, we can go a week without texting and she won't initiate it, I always text her first and she never seems to care how I'm doing. I've tried to make plans to hang out, but she's always doing something else, or doesn't feel up to it.. This has been going on ever since I got back from my (just under) 2 week vacation. She knows what I've been going through recently...she knows I might have cancer, but does she care to ask? To see how I'm doing with it all? I fight every single day not to drink, not to become depressed, not to get higher than I've ever been so I can forget it all. I said I'd go to a halloween party, got really excited, spent $70 on a costume for it, and then my ex fiance RSVPd on facebook that he's going, which means his gf is probably going... I had a full blown anxiety attack, just thinking about it makes me tense and anxious and I asked, no, begged, my best friend to go, she's friends with everyone else going, and knows how hard it's going to be on me but she said she was gonna pass on this one.. Normally... normally she'd go, she'd be my support person, she'd keep me from freaking out, having an anxiety attack, and she'd fight me if I tried to have a drink.. she knows everything that's going on... yet she can't do this one thing for me? I'm beginning to feel as though I have no best friends...only people who used to be my best friends.