I'm never going to graduate

I went to a departmental retreat last week and heard talks from some of the other students in my program. I realise they only chose people who had results to talk about, but it still made me feel incredibly lazy and inadequate. I couldn't even get a poster together (well, I did make one, but I didn't present it because I felt like I'd have to fudge too much to make it look like I'd done any work at all). I don't generally see many other students because my lab is out in the middle of nowhere so it didn't really sink in until the retreat that I'm in my third year now and I should really be starting to get somewhere. Instead I'm just coasting along reading blogs all day.
I couldn't even concentrate on (m)any of the talks (apart from the one Commonwealthlander, and I was really just enjoying his lack of accent), let alone ask a question or think critically about the work.
I guess I've finally reached the limit on what I can do without actually putting in some real effort. My whole life until now I've just coasted along with a few short bursts of activity when something was due, but I should really start developing some work ethic. Everyone else at the retreat was also complaining about having no results/not reading enough etc but they actually do a lot more work than me.
I did have good intentions about starting afresh and being productive. That lasted long enough for me to read a few abstracts and one whole paper this morning (after I got in at 10.30...) but I couldn't take the blog deprivation long enough to really accomplish anything. It would help if I knew what I was trying to accomplish, of course, and my advisor isn't in today to ask for direction.
Since I'm not doing any work, I should just leave and meet up with my friend from home who's visiting, but I'm being avoidant about that. She's staying with me for the next few days, though, so I'd better get over that... I'm happy to see her, but I hate the prospect of no alone/isolation time.
My mum seems to think that my depression is an urgent crisis, rather than the background to my life for a long, long time, so she's constantly calling me and telling me to get tested for hypothyroidism or diabetes and to keep trying anti-depressants until I find something that works. She's happy that I'll have a friend around this week, too (because of course I'll talk to her...). I'm trying not to be driven all the way back into my shell when I'd only barely peeked outside, but I'm not really feeling any more open or understood than before and it's so much easier to just coast along in silence there too.