Seems like you are discovering the truism that the last 10% of a project takes as much time as the first 90% of the project. In my experience, it is always a slog to ship a product. What you are feeling is normal and the experience of many developers. You should plan for this part of the project and figure out ways to motivate yourself to ship something.
It took a long time to train myself to ship at the 80% mark and simply walk away to let it germinate. Over time, you cultivate a garden of nearly-done projects that are all ripe for expansion or rewrite.
