Please help - separation anxiety

I am the one with the separation anxiety....how do I get over the fear of leaving my 4 month old baby sleeping in his own room? I have been trying for the past couple of nights and it’s just very hard and I can’t sleep and I just end up taking him and putting him in his bassinet next to me because I am just anxious to leave him in his room. Yes I have a baby monitor and i do hear him even when he laughs in his sleep, i am just anxious!!!! How do I do it ? How do I get over it?