Hello, newfren here. Just wanna say that this place really makes me feel better when in uncertain times. Thanks lads.
Do deep breathing exercises into your belly through your nose. I'd also suggest looking into bodyscan meditations. If you've ever been involved in athletics, martial arts etc you should find it quick to pick up. Once you get good you can literally 'force' yourself to relax. Great for sleep!
As for deciding what to do, I'd recommend shrimply making a list of things you wanna do in comfy time. I'd also recommend reading the book 'Finding Flow'. Basically, any activity where you can get into deep, enjoyable focus and progress skills. I even use the 'deep focus' mindset when I watch anime or post on boards. When you give something undivided attention, you usually enjoy it more and worry less. I try and avoid distractions as much as possible, especially in comfy time. Imo 'shallow' stuff like messaging and social media can distract and harm you to the point of mental illness (it did to me).
Above all, enjoy yourself fren.