I was prescribed this drug and have been taking it for 3 days now...

I was prescribed this drug and have been taking it for 3 days now. I am taking 20mg and the first time I took it I had the worse panic attack in my life. Second time I took the med I had a a lot of anxiety but then that went away. A while later I felt happy. I was in a really good mod a work but I had some chest pain the lasted all day. then when I got home the pain left for a while. Shortly after eating, the anxiety came back bad. I took some Ativan and the didn't do a thing at all. Which I thought was scary because it usually helps in a few minutes. So it really seemed like I was having a heart attack but I just ended up falling asleep. Nothing happened. The next morning I felt good and decided to take it a third time and I had all the same symptoms I had last night and the Ativan made me fall asleep this time.