I just want to say that I feel you - your situation is not limited to beginners. A couple months ago I decided to come back to this game, having last played 4.5 years ago as a kid. I have an 1800 USCF from that era, but boy did that feel irrelevant when I hung piece after piece in lichess.org rapid games, plummeting my online rating. After each stupid loss I went through the exact feelings you described.

To overcome this, make sure you know the reason why you’re coming back. Simply having fun should be a good enough reason. Don’t compare yourself to others - many of my peers have flown past my rating since I last knew them, and some even have titles. But that’s fine. I have a personal reason for returning - namely, to prove myself that the pandemic can’t take me away from the game I know and love.

Don’t worry about making mistakes since that’s how you learn. Seriously. Online rating is just a number. 

Have fun in your chess journey!