What's the first thing you do in the morning? If you're hitting snooze on your alarm and going back to sleep, you're setting the tone for the rest of the day.
It's easy to justify; you don't absolutely have to get up straight away and nothing bad will happen if you get to work a bit later. And it took you a long time to get to sleep, so you need to make up for it.
But here's the problem; anything that's worth doing involves some degree of difficulty or discomfort. There will always be reasons to delay or to avoid doing what you need to do, or to work on something else, and giving in to these temptations means you fail before you even begin.
To succeed in your PhD, you have to go far beyond the initial difficulty. Once you set your intention, you have to engage with the task and stay with it long enough to solve difficult and frustrating problems.
It isn't always easy to get up when the alarm goes off. Sometimes you have to fight yourself and force yourself to do it. But winning that battle means you're starting the day with a success. You're ahead of schedule, instead of behind.
Likewise, it isn't always easy to stick to what you planned to do in your work and start when you planned to start. Sometimes you have to fight yourself; fight the temptation to check email or do something else you've only just thought of. But winning that battle, following through on that commitment to yourself, gives you a chance to succeed.
This gets easier with practice. Start with the small things, and stop hitting snooze.