Hello~Are you feeling better, I noticed it has been almost a month since you posted this.
The water could just maybe be a little too warm for your system to handle.
I did some internet searching and came up with what looks like would pertain to your condition, it is called carotid baroreceptor function.
In simple terms, think of what happens when you take a hot shower. The body senses high heat so it rushes large amounts of blood to the skin to be cooled. But since the hot water continues to heat the skin, the body tries to force even more blood to the surface to cool in a losing battle (ever notice your skin is reddish when you get out of a hot shower?)
When this rush of blood goes to the skin to cool it leaves the area where is was originally working. Normally, the baroreceptors will compensate so that all of your normal functions will continue, but in some people they are slow to respond. So the extra blood that gets pushed upward toward the brain is not there, it is trying to get cooled elsewhere. This can cause the brain to malfunction and cause a variety of problems (such as breathing).
Bottom line, whether this is the cause or not, take cooler showers. Find a temperature that in warm enough without causing you any problems.