Common problem with that mod, it happened all the time in TL. Basically somthing like you use the mod and then open a chest and it doubles your mana pool. Save before opening chests.
You can use the command "mana X" and reset your mana to it's old level. Incidently you can also just use "mana" to refill your mana as required.
Sigh I really hoped the mod maker had managed to fix that side effect
