I'm not sure what to do about my boyfriend.. I'm worried I'm going to lose him

My boyfriend has issues with anxiety, which made him leave uni earlier this year to take a year out as when he went into lectures he would have a panic attack and would need to leave. But on reflection he thinks that the anxiety may have been heightened by his drinking - he used to wake up in the morning and go straight for vodka and then just be drunk all day. We both still live with our parents so I couldn't try and stop him, and I was working. He lives in a home were underage drinking, cannabis use and smoking from the age of 13 (my boyfriend only drinks, he smokes on occasion but not as much as his younger brother) are all things to be applauded, so I am very scared that he is going to get ill again or start drinking excessively again - we have been looking at flats so that we can move in together for a number of months now, I live in the nicest part of town currently and he wants to get a flat in the same area as where I live already so I think he is trying to get out of his house and get as far away as he can. He is 19 now, but when he was 12 he chose to go to a good school in a better part of town to make a better life for himself and to get away from the bullies who taunted him about his stutter. If he hadn't have gone to this school then he would not have done so well at school, getting A's across the board, and would not have got his place at university but I'm scared that he is going to waste the hard work he put in. He has already decided that he's not going to go back to University this September, but will wait until next year to return but I'm worried that he is never going to return and will waste the opportunity that he has got. He has the ability to do well, and has done so well all by himself and by only getting help from friends, me and my family. Recently, his drinking has begun to get worse again - not drinking alone, but out of the 7 days this week he has been drunk 4 of them and has almost lost his job because he was late coming in the following morning/still drunk. Two months ago when he was drunk he swallowed a handful of pills and told me that he tried to kill himself - he said that he wasn't sure why he did it and that he would never try such a thing again but a few weeks later he told me (while drunk) that he didn't want to be alive anymore. But again, after he sobered up he said he was being stupid again and that I shouldn't worry ( how can I not worry? I tried to convince him to go to the Doctor about it but he didn't want to). His main focus right now is drinking, and because of what has happened before I don't like that he's doing it. Whenever I mention his drinking to him, he gets very angry pretty quickly and does not answer what I'm saying - if its over the phone he normally just hangs up and has a go at me. He thinks I'm just having a go at him, but I am terrified that he's going to do something stupid or is going to make himself ill/make his anxiety worse again - and because he thinks I'm just having a go at him about anything he gets very snippy and we usually get into some kind of argument where he will bring up the fact that I don't have a job right now/that I took a year out of uni/I'm only doing nursing so I'm stupid and he will tell me that I'm a waste of space. I think he is just lashing out because he doesn't want to hear me say these things... I don't know.. I think he's lying to me about his drinking as well, and that he is covering it up - as that's what he did before but when I ask him if he is lying the same thing happens and he snaps. He is not violent, just vocal. We have been together for over 5 years now, and I'm worried that something will happen to him or to us...