"You are not your own, for you have been bought with a price; therefore, glorify God in your body."( 1 Corinthians 6:19-20)
Sometimes we try to live our life and somebody else's too. Let me explain what I mean.
Someone asks you for something and the answer should be "no," but you say "yes" instead. Then you do emotional stretching to make the yes fit your spirit, but like a size 6 shoe on on a six-and-a-half size foot, it won't fit. You limp around in discomfort wishing you had not gotten yourself in this mess. You said yes to protect from rejection you thought you'd feel if you said no. The truth is, you still experienced rejection because you rejected your true self that wanted to say "no." Your true self is someone God loves every bit as much as the person who made the request. You tried to buffer the other person feeling discomfort if you said "no." With respect, My Friend, God did not assign you the caretaker of other people's responses. That responsibility is theirs and God's. See what I mean by living someone else's life? It's too much and God desires you to stop it.
You say no and you feel guilty about it. Maybe you have an overactive guilt valve in your spirit and it hurts overmuch to deny a request. You feel selfish or mean or insensitive when you express the "no"that's in your heart. The enemy of your soul is a major guilt manufacturer. He has locations in every heart, but you can run him out of business with the truth. What is that truth? You are a servant of the King of Kings. When you say no to a request, you are not being selfish, you are following the orders of your King. Your King says you live to fulfill His agenda, not your own and not that of someone else. You spread yourself too thinly, and there's no room for your King's plan for the time and energy He gave you.
There is a time to say yes, a time to deny yourself for the sake of someone else, but may I gently say that you are not the best judge of when those times are? Your sin-tainted heart ( mine too) has a permanent glitch in it that either wants to please everybody all the time or that only cares for its own interests. Neither one is what the King wants.
So how do you know when to say yes or no? Consult your King. Sometimes a tired body is His way of saying you need to say no to a request and get some rest. Sometimes He frees your schedule unexpectedly because He has assigned you to meet a need. Other times He may speak to you in your quiet time that you are to do thus-and-so. You won't know unless you ask Him. It's about having a relationship that is in tune with the Father's heartbeat. It's not a science, it's more like an art, and definitely is a relationship.
So no more living other people's lives. God has given you plenty to do in your own. Trust Him to help them handle your no and you'll always be saying yes to whatever your King wants you to do.