I was on Seroquel for a very long time at 300 mgs and had to be taken off of it this summer when I had a freak experience similar to what you are describing regarding the breathing, but on a more severe level where I had to be transported to the ER. According to my pdoc, turned out that my body decided that it no longer liked Seroquel and that it was going to reject it in the form of an allergic reaction, hence the odd sensations in my chest and the trouble breathing. I agree with folks here in that you should get in touch with your doctor as soon as you can if you should experience any more of those types of episodes again.

As far as it not helping you with sleep, I'm really sorry to hear that. Hopefully, either your doctor will find the right dosage for you or find something else that will help in this regard.