I can relate a lot.
Though I don't feel I have "many" stories to tell - I mainly have two that occupy all the story real estate I have - I feel the hesitance in messing it up.
The story I am currently making, The Changeling's Sister, was originally a "small test story" to see if I could even do this comic thing, before I made the story I ACTUALLY want to make...
My bigger story I refer to as Project Usqara and it would be the one I would write if I could only write one story.
I post only one of my stories on Tapas currently, but that doesn't mean I don't work on the other behind the scenes. It depends on my mood which one I give attention or which one I feel inspired to do. I am also in different parts of the process with the two stories. TCS I obviously have the plot down and just need to actually make the pages, while I am still in the planning faze with Usqara. Whether I will finish that project in my lifetime is a big question... there's ALOT of story to get through there....
So I get the hesitation. Usqara and TCS are both my babies and I would hate to see them flop. But, if I hadn't started TCS I wouldn't have grown either as a comic creator or as an artist as I have. Sometimes, you just have to take the leap of faith and hope the wings will bear.
I feel I went off topic, but I hope some of this might help ^^