Several things of note here...
1. You state that you are i180. You cannot get i180 unless you are wearing 2 180 rings, which would mean you are only wearing one strength ring and something else.
2. Blood of the dragons recast starts when you use it, this means that 60 seconds after that you can use it, not 60 seconds after it falls off.
3. You are not supposed to just burn off all the time of blood of the dragon, you are supposed to maintain it.