Yes, absolutely it can be the Mirena! Hormones are powerful, and as so many women here have attested, Mirena can SERIOUSLY mess them up. (Why this is the case is not entirely clear, but it IS clear that what doctors say about Mirena affecting your overall hormonal balance less than birth control pills is emphatically not the case for many, many women.) You are NOT crazy. There are so many stories on here of anxiety--I had many symptoms of anxiety (heart palpitations, insomnia, in addition to the feelings of anxiety itself) and they all went away after I had the Mirena removed. (And my sex drive has come back!) Honestly I feel like a better version of myself in so many ways since I have gotten off of synthetic hormones and I am SO SO SO glad that I did. It's not worth messing up your body and your emotional well-being!