Ada,
120/80 is generally considered the norm for BP. If you haven't already brought the low readings to the attention of your doctor, you should do so ASAP. Low blood pressure needs to be managed the same way that high blood pressure does. Don't take any chances by not having this addressed by your doctor.
RSD causes many strange things to happen. Since I've had RSD my temperature stays around 97.9 instead of the normal 98.6. The doctor didn't seem worried when I mentioned it to him, but I watch it closely. I've also noticed that I seem to have recurrent infections too. That didn't happen before RSD.
Take care,
EJ