This is a common problem, especially if you work remotely or mostly work at home. To help you stay motivated, consider working in chunks of time. Think about your most strategic tasks and head for those first whilst avoiding distractions. Then you can have a break or fire up Outlook and get some emails done.
You’re probably most productive in the mornings so work with this and don’t get distracted with lesser work during your most productive time.
Rewarding yourself for a job well done is great for motivation and will help keep you on track. Take time to do something you really enjoy.