I have had the mirena (levonorgestrel) since septmber & have had ongoing anxiety around my menstrual cycle. could they in any way be related?

Not likely : It is not likely that the small amount of Progesterone released by Mirena (levonorgestrel) which has a local effect on the lining of the uterus and cervical mucous would cause this. If you have been in birth control pills in the past it is possible that the higher hormone exposure in those had some benefit to decreasing menstrual mood disorders