It sounds like all the surfaces in your room, with the exception of your sofa, are hard and smooth - and hard and smooth surfaces cause sound to bounce around. This is why even small bathrooms are echoey, because they are full of tile, mirror and porcelain all of which are hard smooth surfaces bouncing the sound around the room.
What you need are soft and rough/uneven surfaces, which will absorb some of the sound and stop it bouncing around. Obviously carpets, curtains and fabric-upholstered furniture come into this category, as do books and plants. So the problem will probably lessen as you put more of these kinds of items into your room. Consider sheer curtains or nets as well as heavy curtains as these will dampen the sound during the day when the heavy curtains are open. Also avoid say a glass dining table and consider upholstered dining chairs. If you have wooden floors consider one or two rugs - they can also be useful to define areas within a large room that has several functions, which might suit your set-up well.