My six year old son is starting to act irritable and moody,advice?

Ok lately my son has been very moody and irritable and he just snaps at me for no reason. He also just starts crying for absolutely no reason for hours on end. Its been tough because he dose have Epilepsy . My ex and I are in a court battle because he is trying to get custody from me. And also my son was hospitalized about two weeks ago because against my better judgment I let Nicholas go spend the night at his fathers house. And my ex “Forgot” Nicholas’s meds. And so my son has been sleeping with me and such but the last few days have just be horrible. My son has never been like this, he has always been wall mannered and my little sunshine. My world revolves around him and seeing him like this hurts because I am not sure were this is coming from. Advice?