I can relate a lot to what you have said. I just want to feel some passion again, something to want to get out of bed for; but I really don't know what.
I was sectioned at the end of January, because I completely broke down. Up until I was sectioned I worked full-time; work was a distraction, I do 'enjoy' to work too, but it always seems to become an obsession to be good at my job, more than a will to want to be good at it. I was discharged from the psychiatric ward a few weeks ago now and I am still off work. I am dreading having to go back to the trivialities of work; I have fallen out of life and don't care about anything. Like you, I yearn to grasp that one thing that will give me an ounce of happiness; but I know in my current mentality I won't find it.
I was tried on Mirtazipine, as sleep is a big issue for me; it has a sedative agent and it completely knocked me out and I couldn't function in the day, so I came off it. I haven't heard of escitalopram. I personally hate all of these meds, I don't think meds are the answer for me as they don't seem to do anything. I'm on 200mg of Sertraline and 300mg of Quetiepine a day. I have just started to be prescribed sleeping tablets (Zopiclone 7.5mg), but the trouble is as soon as they get into your system they stop working, so you can't take them every night anyway.
I feel for you, and I hope your current drop in mood isn't too torturous. I know how agonizing it can be. If you want to vent to me any more, please feel free.