It was many years later that my husband built me an extremely large easel. Suddenly, even truly large canvases did not seem so large any more. Previously, when I put a larger canvas on my small easel, it had seemed overwhelming to me, but on the large easel the same size canvas now felt small. I began by painting 36x48. They felt tiny, so I tried 40x60. They were no big deal either. The latest was a 48x72 (shown below). Really, not so much different than painting small.
So here's your pep-talk for the day. Repeat after me... "I can do this. I am in control. It's really no big deal." Now click your heels three times and DO IT!