Non responding meeting

I have been using zoom for teaching yoga classes for 18 months now. The last 3 weeks I have had several classes where my screen (what people see of me) starts to flicker & roll & break up. Then the video goes off so no-one can see me. Then the program wont respond to me. I cant do anything except to end the meeting and try to restart. Even this doesn't necessarily work. I've had to turn my whole computer off and then restart. This has taken up to 15 minutes of messing about. I have students in the studio waiting and people at home trying to attend online. PLEASE HELP! Zoom is a great tool and has become essential to my business since COVID but if I cant fix this I wont be able to continue to use it with confidence.