Annoying toddler

Lost my temper tonight and feel so guilty. 2.5 yo is being so clingy at night. Keeps waking up multiple times and won’t stay in her bedroom. Barges into ours when I’m nursing the baby and has a tantrum demanding my attention. Repeat 6 times all through the night. Lost my temper tonight with it. She keeps asking for boob milk and doesn’t understand her sister needs it first. I’m exhausted.