Every creator's been there at one point or another, so if it helps, you're not alone in feeling this way. The longer you live, the more you'll realize that everyone you meet struggles with some degree of self-doubt, including those who seem the most confident or successful.
What helps me with my self-doubt is to remind myself why I create. As amazing as it feels to receive bits of praise or recognition, that isn't the reason why I do what I do. Even if I had no audience at all, I'd continue to feel compelled to create art and stories for my own happiness and peace of mind, and for their own sake, because I believe they're stories worth telling and they help me develop my skills and improve.
Knowing this, I try extra hard to take joy in the process of creating, completing, and then reading over my own work. I've noticed that when your writing isn't restricted by a fear of how your work will be received, that allows it to "breathe" and become more comfortable, more yours. Focus on improvement, telling the story you want to tell, and learn from the response you get. Let it feed- not kill- your motivation.
All that said, it's wonderful to be able to share with others and see them become excited about your project too. If you have any family or friends who'd support you, don't be afraid to share your story with them. None of mine had an interest in webcomics, but they've surprised me with how kind and supportive they've been, and it's been a great motivator for me.
Best of luck, and keep writing :]