Is this a Panic Attack...?

My boyfriend recently broke up with me. At first I was just sad, I cried and sat around for like a day and was upset. But then, the next night I started feeling really weird. Like my stomach hurt really bad and I was having cramps and then later on that night when I was home alone I felt like I couldn't breathe, like I was trapped. I started shaking and shivering and hyperventilating. It was like honestly the worst thing I have ever felt. I thought I was just over reacting about it, but something about this I couldn't help. It just came I don't know. Can anyone help me figure out what's wrong..?