You’ve already done step one: realise the pattern. Step two is don’t do the new project. See it for what it is, not a great new idea, but another step down the road you’ve been walking down for years. Just because an idea pops into your brain, doesn’t mean you owe it anything. Something that may help is picking a smaller project, so small you could do it in a day or two. Build up some endurance over time. Good luck
Just because we could possibly code some amazing concept project, doesn't mean we'd enjoy it. Or that it wouldn't end up causing us huge amounts of stress.
A lot of us are stuck at home, bouncing off the walls and feeling like we're not doing anything.
THAT IS OK!
We're in a world that is both scary and new, we don't know quite what is going on, and we need time and effort to process that. By "effort" I mean intellectual, spiritual, physical, and emotional. (If you're not religious, think of a workout in a gym: spiritual effort is stretching and flexibility, and emotional effort is strength/weights. Or perhaps that spiritual is subconscious and long-term, while emotional is conscious and shorter-term.)
tl;dr - too much heavy shit happening, don't overburden your head.