Is it normal to be mad at my best friends for dating each other?

A little background info but,
Basically I used to date my best friend, let's call them x.
We broke up because I could tell they were unhappy with me/embarrassed or something like that. We remained friends though.
I later find out x likes my other best friend, y. We're like a trio right, we've been friends forever.
I tried to ignore it, hoping that y'know, x would get over it, but they didn't. Turns out y also likes x, so they end up dating. They're still together, by the way.
And it's not like I still like x in a romantic way, it's not that at all. It's more like, I feel like now that x & y are dating, I've been pushed out of the picture.
Y doesn't seem to treat me the same way as they used to before they started dating x. They used to be fun to hang around with but now they just seem to hate me almost. They snap at me, never joke with me anymore, hardly ever talk to me, etc.
X also acts pretty different with me. I'm sad to say I've definitely grown apart from both of them, and because of this situation I've been incredibly depressed. And they never tell me anything anymore either. Like I get completely it's their relationship, and they have the right to privacy. God I so get that. But before they started dating both of them would come and talk to me about cool things that would/will happen, they'd come for advice, and etc etc etc.
Now the only time they talk to me is if I start a conversation it seems like. It sucks. And the thing that sucks the most is that I am so upset about it. I'm upset at their happiness. Which is so disgusting. I'm so disgusting, damn.
Whatever, is it normal to feel this way? Because it's more than anger, it's sorrow and it's like, i don't know. Emptiness.