This is called Discipline :)
If you feel like taking a break; watching Netflix, eating chocolate all weekend - go ahead. Nothing is wrong with taking a break.
To break out of that habit is difficult sometimes. No one will do it for you and if you have a list of stuff to do, it'll just get longer, the longer you sit around and do nothing.
Start small and tackle a small task / project. As people that write blog articles say; just start writing. Even if the task is so tiny as to waste your time, just get 1 done. You'll feel a sense of accomplishment and have gotten something done.
I personally like to plan. If it's a big task, I'll try to break it into smaller pieces, either on paper or in mind mind. I try to build up the scenario in my head. If I get it done now, I can relax later, or go out and do X once it's done. Remember Trinity in the first scene of the first Matrix? She had just jumped (flown ?) across buildings, landed on her back, knowing the agent was coming and she says to herself "Get up Trinity. Get up!" Do that. Talk to yourself, convince yourself to do it, and do it.