A simple spell, that was created by vaguean on tumblr (who is sadly deactivated now), is to take a bunch of matches, wrap them in red string at the bottom, burn the matches until it reaches the string while thinking of fire pushing you towards your goal, and keeping the bundle in your back pocket as a charm. I also like adding a stick of cinnamon or some oils to the bundle. It is very simple, but works like a charm... no pun intended.
I'm finding it a little strange that you need a spell to give your self energy. In magick all a spell does is intensify energy that you harnessed using your own willpower, and direct it toward a purpose. If you need to give yourself energy simply use the process of collecting energy that you would use before a spell and direct the energy into your body. This can take from between 1 and 20 minutes depending on your level of experience.