The first answer by Ummmm is sound advice. Start packing now.
Get as much done early as you possibly can. Leave out the bare minimum needed to live.
Be ruthless about getting rid of stuff you don't need. It gets easier once you have made a few decisions, and after a while you get pleasure out of binning stuff or sending it to a charity shop.
Most people only have big clear outs when they move house, so take this opportunity to streamline your belongings. Look at each thing and ask yourself if you have used it in the last six months, and if your life would be poorer without it.
Either take regular trips to the recycling centre and charity shop, or if the situation is bad enough hire a mini skip (or even a full sized skip)
You will be amazed how many cardboard boxes you fill, so if you can find a cheap or free supply of strong boxes, do it. Buy loads of parcel tape, and a marker pen to write on the boxes. Make sure each box contains stuff for the same room in the new house, and write it clealy on the outside.
Leave a list out to write down who needs to be advised of of your new contact details, and keep adding to it as new people come to mind.