If you aren't motivated to do your work, reach out for something that motivates you.
A possible partner (boyfriend/girlfriend) could be the one.
Say to yourself that if you do not do it, there may be future consequences, just like the way you are saying to yourself right now.
It could also be that you are stressed, so you find something to make you feel better.
That being said, it makes you even more stressed, if you find something to cool it down.
Take a hot shower and say to yourself "I need to do my work".
If you get tired, work out so there's blood flowing to your brain.
Make a timetable or schedule for the amount of time you are NEEDED to spend on your work.
Make yourself sign a self-created contract in case you slack off. Of course, if you do not fulfill the contract, you face the consequence.
Just remember, if you do not start, when will you start? If you keep pushing it back like right now, as you stated, you will never reach your destination.