Honestly, you are going to run into periods of restlessness and fatigue. It’s more or less unavoidable no matter how creative or interested you are. What you do when you recognize it is more important.
It’s possible that you could find that web development is not for you. How to distinguish whether it is fatigue or genuine disinterest is up to you.
You just have to manage yourself. Realistically look at it as a long term commitment, not a fast track. Just because you breeze through 26 lesson doesn’t mean you retain all that information, and it’s possible that you haven’t hit where the difficulty curve ramps up. This isn’t a test you cram for, so don’t rush. Take breaks and make sure you are really internalizing these information.
Plan out your studying, create a rhythm and consistency and make sure you are progressing, if not day by day then week by week. It’s going to feel like a chore sometimes because part of learning and working is tedious. You just have to keep your eye on the bigger picture and keep yourself on track. Mental discipline is an important part of self-learning