I was on tx and I became very warm and groggy, and could hardly keep my eyes open. I looked over at the machine and I observed that the temp was 37.6. I called for the tech and asked her to lower the temp to 37. The next thing I knew, I was becomming chilled. I looked at the machine again, and this time, the temp had dropped all the way to about 36.2. I called for the tech again and although she set it at 37 again, it kept climbing rapidly to over 38. Finally, another tech stepped in and said its normal for the temp to swing until it balances out again. But I could feel these temp swings and it was making me sick. The machine model is a Fresenius 2008H. Is this true, or does it signify a problem?

It is not usual for the temp to vary more than a few tenths of a degree during treatment, however when you adjust there will be a see saw effect as the temp climbs to reach it's new adjusted value, or drops to reach it's new value (depending whether it was raised of lowered). Normally the temp should be within 0.5 degrees of what it is set for (37.0). You can check what it is set for by scrolling the arrow to TEMP on the display then hitting SET button the temp will show with a ? for adjustment.
Watch the temp during the treatment. If it starts to vary let staff know. In my experience the H machine locks in and is stable.

The temp ultimately registered at about 36.4. On most machines I have had the temp is usually 36.9 or 37 so I had never seen this large a variance before. I felt very unwell at 37.6, and like I said, when the temp was readjusted, I then felt chilled. I came off the tx with a headache. You seem to say the temp as it ended up was in normal limits, but it didn't feel normal to me. Lets say the temp was even furthur off than it was - what would need to be done then? Can the temp come out of calibration causing the tx to be discontinued? Does a faulty temp represent any danger on tx?