"You don't have to be motivated to be productive." -Someone, somewhere. In the internet probably.
I can't remember where I heard or read that quote, but oh boy that hit me hard. You can actually get things done if you have a working productivity system? Even if you feel like s"#%?
I started using Evernote, Todoist and Google Calendar. Pretty basic stuff really. The revolutionary part for me though was finding the - and I hate fancy buzzwords - Pomodoro Technique. Google it, if you want.
Basically I start my day thinking about stuff I need to complete that day and I write them down into my notebook. I break larger tasks into several smaller ones so that they don't seem too daunting and because ticking boxes is great. Then I set a timer usually for 25 minutes and I start just working. It's amazing how much easier it is to concentrate when you know you have to do that only for a short amount of time. After 25 minutes I take a short, few minutes brake, and then I start working again. 25 minutes of work, then few minutes brake. Repeat until the end of work day and marvel all the stuff you've done.