I completely understand your feelings. All writers are paralyzed by feelings of inadequacy at some time. I’ve self-published a few books under a pen name and received some terrible reviews, but I’ve also received some amazing reviews from people who love what I’ve written. The thing about writing is that it’s so subjective and even if you wrote something brilliant, there would still be people who hate it. The vast majority of writing is average but that doesn’t mean it’s not worthwhile. Try to focus on the joy you get from writing and not how it’s going to be received by others. Elizabeth Gilbert’s book Big Magic gives some great advice on how to develop this mindset.