Almost everyone can relate to this problem, find out how to keep on form in the workplace.
If you want to stay awake at work, one of the best pieces of advice I can give you to stay awake at work is to do work that you love. It is only work that is boring or tiresome that is going to make you tired, another idea would be to get an early night the night before and if work really is calling every last little bit of energy out of you and it has been a really long day, then maybe think of yourself, take time out, take a little break, get some fresh air, walk around the block, connect with something more than just yourself and whatever it is that you are focusing on, create that discontinuity with whatever it is that you are doing, go and do some yoga, do some running, whatever, just create a pause in your day, then come back refreshed and integrated, continue doing whatever it is that hopefully you are loving. Another way of looking and staying awake at work is to take a look at what is going on in your whole life and we could take a look at what is going on with how you are eating, take a look at what is going on with your exercise and whether or not you are looking after your body.
Body often gets tired at the end of the day and exercise is a really great way of re-invigorating our body. Take a look at how you are sleeping, what is the quality of your sleep, what is the length of your sleep. If you spend a week with taking 2 hours not enough sleep each day, at the end of the week you have lost a whole night of sleep and wonder you are feeling tired.
Finally, it is important to have fun in your life and also good idea to have some sense of spiritual practice in your life. All of these kinds of things will all come together to help you look after your body, so you can show up to whatever it is that you are doing in totality being the total you, no more mediocre you and whatever it is that you are doing. .