Mirena IUD

Lu
I'm just curious I've been on the mirena for 6 months now not had a period since it was put in and have never been able to feel the strings I went to my doctor and she said it in place but had moved slightly and gone high up so that is why I can't feel the strings but been getting a lot of feeling exhausted and major breast pain feeling sick and feeling faint so was wandering if anybody has had the same symptoms while on the mirena and if anybody would think I might be pregnant I know it's very unusual but just curious ?