Bed Time Probs!

Is anyone having problems getting their toddler to go to bed peacefully? We do not cosleep with our almost 3 yr old and she has been in her own room since she was 10 months old. She was always such a champ at bedtime and we had no issues until this past year I guess.. I don’t really remember exactly when it started. She screams as soon as my husband and I start to leave the room. We have the same routine at night and it hasn’t changed. We use the potty, brush teeth, read a book, and then it’s lights out. We have a night light, leave the door open, and have a picture/ sound machine. We’ve tried staying in the room until she’s asleep to waiting outside her door till she’s asleep and now we can’t even do that without her going ballistic. We just had our second baby which I know is an adjustment but this started before her sister was born. I’m hoping it’s just a phase but I feel like a horrible mother when she’s screaming and I don’t wanna leave her by herself but there’s no winning. I really don’t want to start the habit of her sleeping with us at night as I already have the baby in with me. Sleeping together at night is one of the only times my husband and I have alone, quiet time. Sorry for the long post, but any advice you can give would be greatly appreciated!