Even though my MD told me to take two Ultracet before bed for my ...

Even though my MD told me to take two Ultracet before bed for my chronic neck and back pain, I only took one. I'm glad I only took one, because I had the hardest time breathing and my chest felt very constricted! I got kind of scared that I would pass out and stop breathing altogether. Eventually, my breathing improved and the pain subsided, however, it came back with a vengence along with nausea when I woke up the next morning. The next night, I took half a pill, but the effects were the same but slightly diminished. I've decided to leave Ultracet alone as I'm afraid that I'll stop breathing when I fall asleep.