Real anxiety?

I'm 17 years old. I haven't been diagnosed with anxiety and I don't know if I'm just stressed or if I actually have a problem. I haven't been feeling great the past month or so. I had my first break up last week and I know that didn't help me much. I keep having dreams about school starting up (even though it's more than a month away) and in this last dream I was hyperventilating and just bawling. This did happen in real life a few months ago. I don't know if this stuff is serious or if I'm just over reacting.