Lost what I considered to be my best friend...

I'm here because I have a situation that happened that has me really stressed, really worried, feeling sad, feeling ashamed, feeling mad, everything. I want to chat with someone to get their perspective, to know if I am in the wrong and then see if maybe you can provide me with advice or opinion on how to go about the situation. 

So my sister and her friends were visiting Guatemala from the USA and last night was their final night. For this reason, I took them out on Friday night to party. We drank, went to an afterparty and then went to a friends house to continue drinking. 

I was drinking a lot, I did cocaine and then everybody left. I stayed at my friends house because he lives a few houses down. We ended up doing some mushrooms. 

So a bit prior to that, when people were still there, we started talking about a situation that happened recently where I was mad and our relationship had really been suffering. We talked about it a few weeks ago and everything was good. But we discussed it on Saturday while drunk. He started crying because he felt bad for what happened. 

Anyways, fast forward, everybody left and we did some mushrooms. He told me how he did not want to lose me out of his life and we were really connecting. 

Somehow we ended up kissing, although I don't know if he remembers that part. He then started kind of insinuating himself on me by telling me to lay next to him to which I said no. He continually got very close to me. To which I later told him to lay down next to me. Although I did not do it in a sexual way or anything, but more in an intimate type of way just to connect with him I guess. 

We kind of cuddled for about a minute and then he said he was going to the bathroom. When he came back, he had his gun and was very mad telling me that I should leave and never talk to him again because I had taken advantage of him and that he felt betrayed because he was straight. I am also straight and feel like what happened was more of a bonding thing. So here are my questions that I would like your input on: 

First of all, I do see why he feels betrayed, but what about me? He was part of everything. I should also feel betrayed.

He then blames everything on me, although we are both grown adults, him 31 and me 40, so he knows what he is doing. I told him that I would like for him to also take responsibility on his part in the situation but he continued blaming everything on me.

If possible, I would like for your input on how I can go about starting a conversation with him because he told me he does not want to talk to me ever again 

I feel super anxious about the whole situation, super ashamed, angry, sad, confused. I hate that he is blaming me for everything and I am very sad to know that I lost a good friend 

I do not know how to go about my day today after this happened