One time years ago I told my brother about this amazing idea I had and he was like “Isn’t that pretty much Dante’s Inferno”? Literally didn’t even know the plot to Dante’s Inferno and when I looked it up I had to laugh.
I understand your pain though. It would be awful to work so hard on something and then fear that people think you’re stealing an idea from elsewhere. I’ve even come across works on Tapas that make me pause when I realize similarities with my own work.
I don’t think you should give up on your work. And I think you should take the time you need to make it as up-to-par as you would like for yourself. I made the mistake of trying to make comics when I was new to my iPad without allowing myself to develop my art. It’s not worth not being happy with what you are putting out, just to get it out.
If you really think about it, so many stories share the same themes but are told slightly differently. Or with different characters. People may try to compare your work, but I can assure you that there will be so many others who will appreciate it.