When it comes to over the counter medications that work the best for me are: Alleve and Ibuprofen. These kill the headache pain but keep in mind that they do not help heal your concussion but rather numb the pain.
Other medications that may help you are Tylenol and Excedrin. These had briefly worked for me but my body quickly adjusted to them so they do not help.
I would recommend taking a riboflavin supplement which you can find at most drugstores. The riboflavin that is already in our body plays a large role in how our body makes energy. The headaches you are going through prevents the energy being made in your body so providing it with more can help aid that process.
To also help with giving your body more energy it is important to sleep. Your brain heals the best when you are sleeping and will give you relief from your headache as well as more energy to go throughout the day.
The hit...the bump...the crash 