Blaming yourself...

So two people have passed away and I feel like I could have somehow prevented it or somehow helped them I don't really know but it still is fucking me up inside. 

-New Years 2014 I went to a house party with my BF at the time. I met his friend's family and everyone was super nice and we were all drinking having s good time. Me and the friends uncle got on the topic of movies and talked for a while about scary movies. I went outside to smoke a cigarette and an argument started in the house. I watched through the window as everyone started making fun of/trash talking the uncle.... I just figured everyone is drunk they will get over it. I watched the uncle walk to the back of the house and go to his room. The party went on and he didn't come out I thought about going to ask if he was ok but didn't want to invade his privacy I thought maybe he just went to sleep. We get a call 2 hours later after we have gone home that he went in the bedroom after the arguemenr and hung himself while the party was still going. I blame myself like I should have just gone and checked to see if he was ok it was a bad arguement. 

-November 2014 I was out partying with my friends and we had DDs so we weren't being complete idiots. Everyone besides the DDs were completely drunk and high off our asses. I had sobered up by the time the night was over and so had some of my friends. It was time to go home and Allen was wanting to drive his car home. He got the most drunk out of all of us and even started a fight at whataburger because a girl asked him to meet her there and when he walked in she was kissing all over some other dude. We knew he was drunk still at the time of the fight so we didn't let him drive. We went and ate somewhere and then stopped at a gas station to decide who was taking who home. Allen seemed completely fine and we all thought he was sober enough to drive as it had been about 3 hours since anyone had smoked or drank last. I offered to drive him home since I was sober. My best friend Michael offered to drive him home as well. He refused and promised us he was ok and good to drive. We made him walk a straight line and he did so we wer like alright I guess your good. 15 minutes after I got dropped off at home Allen hit a light post and died. He was going over 100mph and died upon impact. He sent his brother a snapchat 2 minutes before he hit the pole you could clearly see he was going too fast. I still feel like maybe I could have made him let me drive or we should have made him stay with one of us that night and not let him go home. 

How do I stop blaming myself.... or am I right to blame myself?