I agree amber...i also feel worse when the weather gets warmer.
It's a catch 22 really as having low blood pressure coupled with hypothyroid, which makes one feel cold...a hot bath relieves the cold thyroid feeling but drops the BP too much.
I used to love stinging hot baths! Now i have them just 'warm' to not get too overwhelmed. Also it's wise to just add 1 cup of Epsom Salts instead of 3-5 that many use.
I switched to Magnesium chloride flakes instead of Epsom Salts - as i was hugely jittery and fatigued with the epsom. Think the sodium was causing too much sodium imbalance. The straight magnesium flakes really do help relieve aching muscles and joints.