Asclepius: Sorry to hear you are having such a bad day. That is so rubbish about them not talking through alternatives with you or listening to what you are saying. Unfortunately often once you have a label, it sticks, and no one can see beyond it.. Let us know how the Lexapro goes!
I'm fairly new to this thread so I don't know the answer, but have you looked into CBT? Obviously it is best face to face, but there is a really good CBT book called "Overcoming Depression" by Paul Gilbert which I recommend -also a couple of websites (which I found kinda irritating at first, but did actually work - both written by psychiatrists) called
MoodGym and
Living Life to the Full..
Apologies if this has already been tried, I wanted to read back through the thread so I knew everyone's stories but got limited time on BL today!
Hang on in there. Things really will improve, I know you can't see it right now but that is how depression is - it blinds you to the possibility of hope. As chinup said, is there any possibility of getting a second opinion?

Is there anything you can do yourself to feel like you are moving forwards a little? Even tiny baby steps.. anything at all that will help to make you feel like you are not just stuck..
chinup: Sorry I've not returned to post anything more yet - been settling back in to Bristol the past few days and has been a bit hectic!
I'm a big advocate of CBT as you might have noticed, hah. It doesn't always work for everyone though. Having said that, sometimes people just aren't in the right place for it to be able to work - so I would definitely give it another shot now. It took my boyfriend 3 courses of CBT before it worked at all, but when it did he went from being unable to leave the house to being a happy, confident person. He said the difference was having a therapist he trusted, and it finally clicking into place how goddam hard you have to work at it and how you need to be pacticing constantly (well, tapered up, haha) until your brain does it automatically.. It doesn't solve everything, certainly, but it is a good tool for negative thought patterns. I don't like the sound of your "fallback plan" at all and I am very glad you want to address that!
Don't beat yourself up about the weekend. It sounds like having a nice time with your boyfriend was exactly what you needed! Everyone needs to let their hair down sometimes, especially when they are going through a hard time. I hope you have managed to eat a little more since then.. and are popping plenty of vitamins etc
I hope you are both feeling a bit better now. You both deserve to be, anyway!
edit:
dp - I love this:
We tend to not give ourselves enough credit for the potential our brains have to see/sense what we need. Let me know if you have any specific questions, I can try and answer them.