I had seizure after having an energy drink. Why?

Hi doctor,

I had a grand mal seizure two months before after drinking an energy drink. Since then, my sleep has become progressively worse. I am a nurse and worked the last three long days. However, I slept for one hour last night, and I was wide awake. I took the maximum dose of Melissa for the dream to assist me, but it did not work. I have also tried Valarian, but I still awoke at 3 AM. I used Melatonin for one week, which did help me sleep, but I felt like a zombie during the day, and I became so severely constipated. I also feel that I am hyper salivating. I am aware of too much sensation in my lips, which has been new since the seizure. I also had a feeling of stress in my chest for no reason after the seizure. I guess it is still there most of the time, particularly when I cannot sleep. I have been to my general practitioner (GP), but I have to wait for a neurologist review. I had a computed tomography (CT) brain, which was fine, and I will have an magnetic resonance imaging (MRI) in two days. I fear that this is hormonal, and I will be left like this long-term. Any of your help would be appreciated as I feel I am losing my mind.