You need rapid prototyping, at home.
When you apply the same level of professional rigor on a private personal project, it easily results in over-engineering.
It is perfectly acceptable to set a high standard for a personal project, but you must understand that you may not have enough resources (coding hours, in addition to your 8 hours of daily work) to make progress on the project.
What is the most essential goal in your pet project? To prove the usefulness of one of your insights? If this is the case, then trim down the project until it becomes a proof-of-concept project. Then, use rapid prototyping so that you can accomplish more with less coding time.