Hey Sulli,
I can relate to what your saying, I'm sure we all can. We live in a world with an infinite amount of distractions at our fingertips. Add procrastination into the mix and you have all the ingredients necessary for unproductivity.
Life in general is all about perspective. The best answer for you will depend on the kind of person you are and your experiences, but If I could step into the Delorean and give myself some general advice on the topic it would be this.
Don't see motivation as a wave that will carry you through your project. If you do then you will no doubt start something, get obsessed with it for a while and then totally slump before looking for the next wave/game-idea and repeat the cycle.
Take a moment and really decide if you want to stick this thing out (and also how much time you want to put into this project as a whole). If you decide to continue then do so knowing that a lot of the development time wont be fun. Depending on how quickly you want to get your game out you might also have to make some sacrifices (both in your game and out of it). This in itself is very demotivating but will ultimately determine whether or not you end up finishing this game.
Now when your sitting on your board and there isn't a wave in sight. Remind yourself that you have committed to the above and not seeing this one through will truly only have you repeating the cycle indefinitely.
If you ever feel overwhelmed with the amount of work don't struggle with getting motivated, don't question your commitment, just play some music ( Something that will go on for a while like this playlist : youtube.com/watch ), put your head down and force yourself to tick one of those boxes on the to do list. With any luck you will find yourself losing track of time and before you know it you will again be swept up with the same burst of motivation you started with.
To sum up: If your bored blame the music and not the project and switch it up. Focus on your goal, don't let yourself even entertain the thought of starting something new before this is finished. Life is a rollercoaster and so is game development, enjoy the ride! :)