I also understand making promises and commitments to others at the expense of ones self. That's a hard thing to change, especially if you are a giver. Even more so if you are a giver who was taught that doing other wise would be selfish and selfish is very bad. I was pretty much taught that. You see that it is a problem for you, so just baby steps then right? Try saying no, even just to one small thing, probably will feel awkward and bad, but maybe good after? After you see that it was a good choice, you can start to feel good about honoring your own needs as well. Honoring ones self starts to feel pretty good once you get used to it. I think a lot of us were never taught to feel comfortable doing it.