When thinking whether or not you can do your best today, or 5 days from now let me ask, why wouldn't you? The only thing stopping you from doing your best is yourself, think why did you start doing this, imagine the wonderful feeling of accomplishment instead of sorrow and doubt. Don't let this bring you down to the extent you no longer have the motivation to be the best you there is. Cause we know how great you are even if you don't see it, so I encourage you to the best you there is.