if you are eating any hard stuff such as coffee, sugar, nicotine, social networks, news - stop. than, when mind will be more clear, do no do work you are not payed. if you do not know if you will be payed, ask responsible person if you should do some part of work or not, or assume it was not explicitly asked means not needed.
in free time you have do yoga, training, walks, meditations, talk to people(relatives, friends).