One thing at a time or all at once?

I'm still no expert at project management using the gantt chart method. I had the sinking feeling I hadn't accomplished all that much from my last attempt at this kind of self-organisation, but I was surprised to find that the contents of my last chart were for the most part all dealt with in one way or another (except for the backload of video editing of performance documentation, which has made its way onto this chart, hopefully not in vain!). Doing this has made me feel as if I have no time, rather than making me feel calm and collected. Not sure if I'm doing this right...