Writing a book is hard!!

Writing a book can be so hard sometimes. Like, when you have that problem where you just can't write. I refuse to call it writer's block because I have plenty of things to write. Things that will be very important to the story. I just have no motivation whatsoever to continue the story. I've let it defeat me too many times on too many stories and I refuse to let it win once again. I really need to get past it because it has been way too long since the last time I sat down and actually wrote something. If you've ever had this problem, how did you get past it. I've been reading and writing on other things. I heard that reading and writing other things helps, but I hasn't for me. Any other ideas?