Hearing myself only in calls

Hi, I’m having trouble with calls. When call starts I start hearing myself. Actually I hear all noices in my room. I work in customer support and when call starts I hear all other coleagues, myself, mouse clicks etc. When call ends I stop hearing that noises.
Playback option in windows is unchecked. I’m using Sennheiser HD450BT headphones and playback option is also off in options.