First off you have to remember that pretty much everything in dreams, when it's not a direct memory at least, is totally symbolic. So that, no matter how horrible something appears in the dream, most things that happen have a meaning other than the obvious. The heavy rucksack for instance could well be your life's 'baggage', the stuff that's weighing you down in waking life. The files you're trying to download could be symbolic of a need for hidden knowledge, stuff you think you need to move forward with your life that is being denied to you. Like you don't seem to be able to get these things in waking life so you're going undercover in your dreams, like a spy, and trying to get the info you need.
Perhaps you also believe, at least subconsciously, that your ex, or the memories connected, is part of what's stopping you from moving on?
There's some stuff about colours here:
http://www.meaningofdreams.org/Dream...lor_dreams.htm
Once you start thinking about your dreams as a series of symbols and metaphoric images, and what these images mean to you - their connected emotions - and mostly ignore what they are literally, like your head being cut off, you may find it easier to make sense of them.