She cheated on me with my best friend?

The title really says it all really. I just feel so hurt and betrayed right now that they were seeing each other behind my back. In all my relationships I've been cheated on and it just really hurts.
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Both she and my best friend revealed it in front of all our friends and I left angrily. The annoying is that we are all at uni doing the same course, and me and her met as a group of mutual friends like this before we started seeing each other so now I feel like I have no friends to turn to either. They're all backing those two too so I just feel betrayed by everyone. Luckily it's the holidays right now but I don't know what I'll do when I get back. I obviously need to find a new group of friends but it just seems so difficult right now.

At the same time, they're all trying to text me and make it out as though it's my fault. They all say I'm being unjust for being angry at them and it's really pissing me off. Then at other times they keep coming back to ask how I am (including my best friend) and I don't get why. It's like they're toyying with my feelings.

I don't even know why I'm writing this. I just feel absolutely alone now. I've tried going out yesterday, doing stuff I enjoy but it's always on the back of my mind and j just feel like going home to sleep. But then I can't sleep and just constantly feel like vomiting. I've not been eating either because my appetite is all messed up.
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How can I move on? I'm thinking that to get rid of my anger, I have to somehow forgive them. But that's not easy.

The title really says it all really. I just feel so hurt and betrayed right now that they were seeing each other behind my back. In all my relationships I've been cheated on and it just really hurts.
*
Both she and my best friend revealed it in front of all our friends and I left angrily. The annoying is that we are all at uni doing the same course, and me and her met as a group of mutual friends like this before we started seeing each other so now I feel like I have no friends to turn to either. They're all backing those two too so I just feel betrayed by everyone. Luckily it's the holidays right now but I don't know what I'll do when I get back. I obviously need to find a new group of friends but it just seems so difficult right now.

At the same time, they're all trying to text me and make it out as though it's my fault. They all say I'm being unjust for being angry at them and it's really pissing me off. Then at other times they keep coming back to ask how I am (including my best friend) and I don't get why. It's like they're toyying with my feelings.

I don't even know why I'm writing this. I just feel absolutely alone now. I've tried going out yesterday, doing stuff I enjoy but it's always on the back of my mind and j just feel like going home to sleep. But then I can't sleep and just constantly feel like vomiting. I've not been eating either because my appetite is all messed up.
*
How can I move on? I'm thinking that to get rid of my anger, I have to somehow forgive them. But that's not easy.

The most important thing to do is forgive them. It may seem ridiculous but the only way you will be able to let go off them (it would be ridiculous if you became freinds with them again) is to forgive them. When you do that eventually your animosity towards them will go and you will be able to fully move on from them.

What reason are your friends giving to suggest it was your fault? Was your relationship with your girlfriend toxic?
I don't mean to sound against you, but I can't imagine why your 'friends' would back a cheater over you? It feels to me as if you're not telling us something.

It's a completely fair question and I appreciate the honesty. I guess none of them really knew we were in a relationship until she dropped that bombshell on me (we liked to keep it quiet) so maybe they don't get the full story either. All these friends were friends with her before they met me so perhaps they have some sort of bias towards her. They've never seen me angry either so maybe that was a shock to them.

But I don't think I've done anything wrong. Sure we had our ups and downs but don't all relationships? *