So I've had this really bad habit my whole life of just cutting people out of my life. It can happen for a variety of reasons either we've just grown apart, they betrayed me, or I push them away. The past few years I've tried really hard to undo this, but recently I've been getting the urge to start cutting people out of my life again. I've been going through a pretty hard time this past year, and I haven't been able to get support from the people closest to me. I either don't feel comfortable talking about it with them or when I do try they are busy. It's been making me think that I should get new friends. It's really bothering me too because a lot of these feelings are directed at my best friend. I've gone through four bestfriends in my life so far, and he's the best one I've ever had. I don't want to lose him, but I just don't feel like he can support me the way I need to be supported right now. I don't know how to ask for support, because I'm usually doing the supporting and making people feel better. I don't really know how to tell them or what to do.
True friends always support each other. It sounds like you have been supportive. Now its time to see if he will support you. If he's a true friend you probably shouldn't even need to ask, he will know when you need the support.
Ask him to hang out, just the two of you, and then try to just talk. Say whatever comes into your mind. People can't know what's bothering you unless you tell them. I often prefer to be alone when I'm upset and my girlfriend is the same way. Because of that, my instinct is to give people space when I pick up that there's something wrong. It's possible your friends have noticed you're having a rough time but assume you don't want to talk about it.
