Photoshop Imac Catalina issue - glitch pictures

Hello, I have just bought Imac (Catalina) and installed Adobe Photoshop trial version for the beginning.

After few hours of working the picture which I drew became glitched, and every little touch with mouse make more glitch.

The glitch is irreversible, the background of picture become black and with strange pixelated strippes/squares, also, all colors which I used became black. After restart everything works fine, but the illustration which I saved is still glitched and with strange background. Is there any reason why it's happened, is there a problem with Photoshop, or it might be the computer problem?

Thank you very much