TERBUTALINE side affects

Hey guys. So my dr just put me on  TERBUTALINE to stop the contractions Thursday and from going into early labor. I was 32 weeks last week. Now I'm at 33. I was a little hesitant about it because he warned me about the side affects of it. I took the first pill and it scared me! It was like my heart was racing. I went online and did a little research and I haven't taken another pill. I'm