I don't even really know where this goes. I'm just venting

I've been working on the concept of 'boundaries' for a few months. For a variety of reasons, I don't appear to have many and it's had a bad effect on my life. I finally figured out last year that a lot of my problems stem from a) not having good boundaries in the first place and b) letting interpersonal issues build up until things are so bad there's no fixing the situation.

I'm trying to do a better job of enforcing boundaries, but it is such a struggle. I hope it gets easier. I've started volunteering with an organization that seems to have some scope creep issues. I volunteered a few months ago to do something without fully understanding what was involved. I gave it my best shot and decided I wouldn't volunteer for that task again.

They asked me to try again and I said no with a brief explanation why ... and now a different person in the organization asked me, even though they knew I had already said no!

I said no again, but the amount of energy it takes me to say "No" and the anxiety I feel around it are really frustrating.