My puppy cries if I leave her sight, how can I get her used to being alone?

I have had my puppy (border collie 3M) for a few days on her own, she was previously with her mom who is my parents dog but she moved with me across the country. She’s great, we’re working on potty training and she does not cry when she’s on her crate (even sleeps most of the night). The only issue is she cries if I leave the room for a second. Since I have roommates she can’t free roam through the house and I can’t let her cry if I leave the house. I really want to train her asap to not cry in my room when shes alone because I need to leave sometimes and I go to the gym. I wfh so I’m with her most of the day. I also heard letting her cry is not the best idea nor do I want her to hate her crate but it is where she would bee if i leave the house.