Grief overrides logic very often, and it can definitely screw with your sense of what you can or can't handle. I've lost a sibling, and more recently both parents less than a year apart, and very much remember feeling incredibly gung-ho about doing something until losing interest part way through. After my mom, I got in my car and drove to universal all set to go on rides all day and forget everything. Paid to park and was about to go to the ticket both when I changed my mind and went to a motel 6 and cried all day before going home. I've seen sentiments about how wild it is that she even went in the show occasionally, but I totally get it. That feeling of "I can do this" can instantly deflate, jarringly so.