Trick your mind into thinking that you are running a routine, something you already have been doing for a long time. Trick your mind, confuse it, deceive it, make it dizzy, make it shut down. You will need to continue for a long period of time. Make you mind think that you have already arrived. Make your mind think that this is day 120 instead of day 21. Confuse your mind about how many days are still left. Let it think – you are almost done. Grab a random day sequence every day. Fool it. Until one day you will be done.