Separate emotional baggage from emotional litter. Baggage contains things you may need on the journey/when you arrive: litter is just messy and depressing.Sort little and often, and throw out something every day, even if it's only a couple of pieces of paper.
Go with the moment - if you feel like sorting out but it's a strange time, so what? Put on some energising music and go for it.
Sort a small, achievable area, and try to keep it clear (OK, at least until you start another bit!)
Take a trip to the charity shop/dump straight away, that day. Don't start to fill a box you'll take later.
Good luck!