Last Sunday I did a 68 mile ride (3 hours 50 minutes). All during the ride I felt great (tired, but great) and then I got home and had a shower, changed and had somethnig to eat, then I went to bed. While lying there I noticed I was only breathnig in a tiny amount, I'm talking a TINY bit, roughly one mouthfull of air every four or five seconds. But I was still getting enough to keep me alive (obviously). Every time I tried to breath deeply I got a weird feeling in my chest and lungs and started coughing violently. It went away after about 30 or 40 minutes.

Is this a normal thing when you push yourself? It was the longest ride I'd been on. This was the only time this happened to me.