I work as a Rails dev for a tiny company (< 20 devs, B2B, different internal apps for companies like a language school, an electricity trader, digital signage

I work as a Rails dev for a tiny company (< 20 devs, B2B, different internal apps for companies like a language school, an electricity trader, digital signage agency) and I'm currently the only person responsible for three projects that have all been going on for a year and are all in the "the last 20 % that takes another 80 % of the time" stage. Yes, I feel like I'm spread too thin. I have to rotate work on all three (or at least two) of the projects every week and every week the clients expect me to deliver new stuff and actual, new, visible functionality. I am not having a lot of fun and I'm hoping this ends soon. I'd like to do some something on the side (not really a side project, but maybe a toy macOS app, play with some new technology or finally start a blog), but I'm currently too mentally exhausted.