Posted: 20/08/2014 at 12:37
+1 to what Duda says although it would help if you give us a little background as to your swim experience and also a little of your swim style if you are aware of it
Do you swim with 'windmill arms'?
You say you breathe every 2 or 3, but are you taking in enough air?
Are you exhaling underwater?
What's your body alignment like in the water?
Do your legs sink causing drag?
Check out Swimsmooth or Total Immersion for some valuable hints and tips