Return of depression with return of uni

I'm currently on a course that I'm not enjoying. I enrolled on the course as I've been recovering from ill health and I needed to get back into the real world after several years out, and I also needed some experience of study in order to get on the kind of uni course that I want to be on.

I now have unconditional offers for the course I want to be on, but I obviously don't want to just give up the course I've been studying all year. I only have 5 weeks left of this course but classes start again on Thursday and I can feel my depression creeping back. I thought I was making progress with my depression, but it turns out that I was probably just feeling less depressed because I didn't have to think about this course.

I've kept up with my assignments throughout but I have one due for next Sunday that I haven't started yet, and don't even want to think about starting, and I know I have at least 4 assignments plus a work placement to complete alongside my studies before I will have passed. I just don't know how to motivate myself or gather up the energy to do it. The work placement is very dull most of the time - scanning makes up a large part of it, as well as 'research' and my eyes are so tired of staring at databases. It feels doubly frustrating to have to sit through classes and complete assignments when I have a reading list for my desired course to work through that I'm actually excited about.

I should add that I am on anti-depressants (I finally opted to try them about 6 months ago) and I'm also on medication recommended by my doctor to try and tackle my PMS, which seems to be a huge trigger for my depression, but still the depression comes back. I think it's more situational than anything - so, ideas on how to lessen the situational depression when I can't currently change my situation?