I agree with both remar and sstitanic2. Sounds like either claustrophobia or anxiety. I suffer with both. A fear of enclosed places will cause extreme anxiety, which causes changes in breathing, heartrate etc. many phobias are a form of anxiety.
It could be claustrophobia. I would check with your doctor before your symptoms get worse. God Bless
This sounds like anxiety. What other symptoms are you having? Have you seen a Dr about this? Remar