Camera and mic not working only in Zoom

Please help me as I found no way of solving this bug. Everything worked fine yesterday, but today Zoom just won't see my webcam and mic, the headset works fine - I can hear the sounds, but people don't hear my voice. The test failed, the camera is in the list chosen as main, but I can see only a black screen. So I checked my camera and the mic - they work fine, but not in Zoom! I'm so frustrated as I teach online every day and have paid Zoom for good connection, longer lessons and a permanent link! I spent all day trying to reinstall Zoom, update drivers, restart my laptop, change cameras, but no result. Zoom doesn't see my laptop camera either! Please help.