I have only been taking 20 mg Lisinopril for about 5 days now. I ...

I have only been taking 20 mg Lisinopril for about 5 days now. I actually started to notice I was feeling better, my headaches were gone and I could breath better, but about 3 days ago I started to get horrible heartburn, flu symptoms and I haven't been able to get more then an hour or so of sleep before I wake up to shaking and my heart racing.This is the scariest thing,I work overnights and I have serious sleep issues already so I feel like crap. being that i have only taken this med for 5-6 days does anyone know how long it will take to get out of my system? I was thinking about starting to take them again just to see if it was something else, but after reading these posts I'm not touching that EVER again.