First and foremost whatever you do make sure you keep a list of what you've done. That way you can look back at it at the end of the day or week and see what you've managed to achieve.

Even if the list only contains a few really small things having evidence of what you've achieved in an easy format to look back on will really help.

Secondly, take each day at a time. Today might be a bad day in terms of getting things done, but tomorrow could be the complete opposite. Alternatively tomorrow could be crap too, which is equally fine.

Thirdly, in terms of what to do then start small. Start by picking up 5 bits of trash and putting them in the bin and build from there.

Finally, good luck. It might not be easy and the path won't always be straight forward, and in fact might go backwards sometime but you can do this.