Separation

My daughter will be three in 11 days. Is anyone else going threw a separation anxiety phase. She has been freaking out at night for bedtime (she never used to) I would be able to read a book and kiss her goodnight and leave. Now she wants me to stay and cuddle takes over and hour now to get her to sleep. She wants no one but me. I only get an hour of time to myself and it’s after the kids go to sleep. She’s also doing it when I leave for work. I need advice on what to do to get her to calm down about me leaving.