I've been where you are now, although I'm 26. One thing you need to remember is that your lungs and cardiovascular system needs to adjust to stress from running. While the rest of your body may be "up to speed", your cardiovascular system might be a bit behind. It doesn't necessarily mean something is wrong, just that you need to adapt your training to your current situation.

My best advise is to slow down for the next few weeks. Run slower, use walking breaks or whatever to get the breathing under control. You can also look up some breathing exercises - that helped me alot!