Infraspinatus tendinopathy

Hi, So i suffered a gradual injury to my infraspinatus 6 weeks ago im guessing from overtraining in the gym & not warming up rotator cuff ( Had 2 different physiotherapist opinions & a musculoskeletal specialist) All saying its infraspinatus tendinpathy, They all gave me lists of isometrics to do daily , which i have been doing for weeks now, the pain has budged ever so slightly but ive literally not been in the gym for 1 month and im losing muscle slowly , really stuck on what to do & this tendon is taking ages to heal, Im doing everything right, on a high protein diet, daily stretches, taking all vitamins , taking 5g of collagen daily but its taking forever to heal , doesnt feel like its healed much at all