Possible Suggestions of what's going on?

Hello,

Just a little over a week ago, I woke up one night feeling that my bladder was somewhat full and I immediately went to the bathroom to relieve myself. I then noticed my limbs went weak and my heart rate began to go up; I quickly told my parents I wasn't feeling well and asked them to take me to the hospital. They began to tell me to relax as I began to tremor uncontrollably (not "the shakes" or "Shivers"); I went into the ER that morning. They did EKG, Blood tests, urine test, and they monitored my heart rate. During the course of my stay, my tremoring stopped after a while. My heart rate though, did remain somewhat high until I left. The doctor and the nurse(s) told me later that it was a viral infection of some kind and that it was nothing to worry about. All of the tests came back fine. I went home feeling a weak and later that night, I began to tremor again.I went to the doctors office the next day and I told him how I felt and he quickly diagnosed me as the ER did the previous day, a viral infection--Perhaps the flu or the beginning of something of that nature? He also mentioned that I could've been having panic attacks as a result of my wandering mind. During the course of this week, I have: been feeling weak and also somewhat numb/tingly arms at times, headaches, soreness, pressure by my groin area, a dripping sensation in my chest that's been here for a few days now (almost as if I'm sweating at my chest down to my stomach-on the inside), slight pressure/tightness in my chest, and some light headedness. I've also had difficulty sleeping for this past week. I went back to the doctor again, to tell him of my dripping in my chest and continued other problems. They had a chest x-ray done as well as another blood and urine test. After all of that, the doctor told me everything came back fine.  The doctor also told me to let whatever is going on inside my body, run it's course for the next week. He also told me to not worry so much about it. After mentioning these symptoms, what do you think is going on?