[squidlogic]

Sometimes that fear can be a good thing. It means you are trying to do things just outside of your comfort zone, which can help you grow. If you are always 100% confident that you can do something, then that means you may be at a plateau in your personal growth. Run towards the fear.

Some specific advice that might be useful...

Bring in other people to your projects. It helps vet the idea, gives you someone to lean on if you're having an off day, and it is a huge intangible 'good' to know that you're in it with someone else. I'm reminded of a GK Chesterton quote, "It may be conceded to the mathematicians that four is twice two. But two is not twice one; two is two thousand times one."

Second, bite off as small a chunk as you can at a time. Not just in terms of features, but break your work down into one or two hour tasks. Sometimes this is not possible, but more often that not it is. Write all of these small tasks down. As you finish one, cross it off. At the end of an 8 hr day of work, even if you have no user-facing features to show for it, you will have a sense of accomplishment over these 4-8 tasks that you were able to finish. This can help act as a positive motivator to push forward.

Good luck!