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Maybe this "sabbatical" will give me time to finally flesh out that portfolio...[/hide]
I got worried enough about you to actually watch a dumbass youtube video explaining scrum.
In all seriousness, take some time off to just go to a beach or somewhere and relax alone. Away from the world. And yeah, then continue focusing on getting your stuff together to hopefully move on to another job in a few months. Don't beat yourself up too much about your portfolio quality, you are likely doing work comparable to any other designer and just have a few passion projects that show off the peak of your technical skills. Honestly, it might not feel like it but another company would probably hire you at a much higher (ie competitive) wage in a heartbeat so it's worth trying to interview at a few places just to see how they react to your portfolio.
Also, and I'm still being serious, you need to start annoying the manager who threw that chart masturbation shit at you. Try creating a gantt chart in MS projects or just use an Excel template and update him with that as often as you give scrum burndown updates. It makes you look like you're trying harder, it keeps you motivated to annoy him/her, and it even has a slight chance of making the manager take a step back and realize that focusing on milestones so much makes them blind to quality