Is your internet connection disconnecting or just pokerstars?
can you access any other sites or continue streaming whilst you have the green bar?
though streaming can hide problems by its buffering.
It could also be your computer getting locked while cpu and memory are busy on other processes.

If you are using wifi, it could be a poor wifi connection if you modem is too far away,
I get similar when I try to use pokerstars in the kitchen which is at the limit of my range.