If it was a mild concussion your CT and MRI will most likely be negative, but that does not mean there are not short-term physical or chemical changes in your brain. Take it easy for the next few weeks, with no exercise or other physical exertion. Also, try to stay away from stressful situations (even loud and crowded places, and using the computer or watching tv may trigger your symptoms). It may even help to take a week off work if you can. This is the most important time in your recovery and if you do too much your symptoms may last alot longer than 2 weeks. I wish someone had told me this after my last concussion. I tried to push through the symptoms and it made it alot worse. I am still unable to exercise 5 months later and I still have dizziness some days, although I am slowly getting better. The majority of people recover in a 2-4 weeks, but 5-10% have symptoms lasting longer. If you rest, you will more than likely be back to normal soon. Once you feel symptom free, gradually go back to your normal activities, such as hiking. If you feel the symptoms again, back off for a week and then try again. Don't worry about it too much - this is not a permanent condition. Just take it easy.