I had similar symptoms that were really getting annoying, often pretty bad after a really hot shower (tough getting out of a nice hot shower in the winter ;-)).
So I bought one of those medical shower stools for like $20 on Amazon, I have to say it really is a big help. At first I felt kind of like an old invalid using it (well, often feel that way anyway, lol) but then I wondered why I didn't think of it sooner, even if just to get that little bit of extra rest vs. standing. Sometimes l take it out if I'm just taking a quick shower, but it's actually so relaxing and nice to sit in the water as it rains down on you that I started wondering why showers don't come standard with some kind of flip down seat or portable seating accessory. Seems crazy to stand up now.
You still have to be careful not to have the water too hot or stay in too long, but it's definitely a big improvement over standing. The thing with the stool is that even if you're sitting directly under the shower with scalding hot water pouring down on you (guilty
), you can still keep your legs almost totally out of the water. That acts somewhat as a coolant for the blood as it circulates through your colder legs, and seems to prevent your body from overheating as quickly. I would say the stool has roughly doubled the time I can stay in the shower, or more, if I wanted to stay in that long.
One word of caution: on the stool I got, at least (think it was this one:
http://www.amazon.com/Ez2care-Adjustable-Lightweight-Shower-Stool/dp/B007HCCS7C/ref=sr_1_2?ie=UTF8&qid=1348928205&sr=8-2&keywords=shower stool ) the feet are that really noxious mercaptany rubber. I had to leave them outside for a week or two before using them, which got rid of a lot of the fumes, but not all of them. After another couple weeks the majority of smell was gone, so even if you're not especially chemical sensitive, you might want to take that into account if you decide to try one. I think most of them probably have those to prevent slippage.