Anyone in med school, any nurses, doctors, etc?

Anonymous
*YES I'm going to the doctor soon. *

But I was wondering if anyone could give me an idea of what my problem is caused by.

I'm 18. I have had no medical history at all. Nothing runs in my family.

-my resting heart rate is usually between 85 and 105. I think typically its 92. I know I'm somewhat sedentary but I don't think that's the cause. I do light body weight exercises everyday and go for walks (sometimes 10 min, sometimes an hour.) About 4 months ago I went to the doc at Walgreens because I had a sinus infection and she took my pulse and it was 120bpm. She told me that that's not normal even if I was sedentary.
-My fingers/hands shake badly, all the time. I can't hold a pencil without it jiggling.
-I get light headed and faint easily especially when standing for too long. Everything will go black and I'll pass out if I stand for over 20 min. However if I'm walking I feel fine.
-my heart palpitates about 3-5 times a week.
-I get very frequent panic attacks. I've done so much therapy taken meds etc but I still get them and they usually have no trigger. Suddenly my heart starts pounding very fast and I panic. I will bolt upright in bed feeling like my heart is in my throat.
-when I lay down my legs jump a lot.

And starting a few months ago I pee a little (like a few drops) randomly throughout the day so I have to wear pads. I don't know if that's a related symptom.

ANY ideas? I used webMd's symptom checker and the only legit sounding cause is a heart rhythm disorder.
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Anyone in med school, any nurses, doctors, etc?
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