SO Sorry that you are having bad side effects on the Letrozole @SamL890
.. it happens to some of us - it happened to me :(
Does it get better? It 'can' ..... but I didn't cope with it either (as I already came from an arthritic background & it compounded it bigtime) ... so I swapped over (after a break from the Letrozole) to Exemestane. It suited me much better than Letrozole for 6 months. But then, I ended up on Anastrozole (been on it for 5 years now) & it was the best of the LOT for me. Matter of fact, Tamoxifen is the only one I HAVEN'T tried!
I would suggest you contacting your Onc for an urgent review .... You have given Letrozole a 'good shot' and your body is not liking it ... you DO need some quality of life, if you are to continue taking the AIs ....
Do you have a Breast Care Nurse? She might be able to go in to bat for you as well ;) She would hear similar stories from other women ... and at the end of the day, we all know our own bodies ....
take care & all the best xx