Learning to say NO!

so, lately god has been teaching me a lot about saying "no" to things. i have a tendency to over work myself and to commit to everything that i think i should do. i am slowly but surely starting to see the need for allowing myself to say no. so many times when i'm approached with opportunities, i always feel guilty if i say no, but i know that this is not what god wants for me. even if it is something "good", i can't do everything. it feels good to be in a place in where i'm saying "no" to things and not over doing it.