It's ok to say no. Go ahead and do it right now. Why not block the whole week and say no to every request that comes your way, just so you get used to the idea (and feeling) of actually doing it. We say yes to be nice. But that "yes" comes with a price, and usually, it's not in your benefit to do so.
So, whenever something does not align with my company or personal goals - I say no way jose. Trust me, you won't hurt anyone's feelings either. You'll be doing yourself a huge favor by saving that precious time to do what you want, and not what someone else wants.
Plus, when you start saying "no", you start to set boundaries. That's huge. Now you begin to take control of your life and shape the contents of your day. Depending on how many factors you control in your life, this could be that lynch pin that makes all the difference for happiness.
You might say, but I can't say no just like that right? Sure you can. You can even sugar coat it to your superiors, so they won't mistake your righteous personal decision for indignant rebellion. Again, if the request does not align with your goals - just say no.
