Newly diagnosed 3 year old suddenly cries about going to daycare

After a late evening emergency room visit due to a bad nosebleed, my son was diagnosed with Acute ITP and admitted to the children's hospital (Via ambulance) for an IVIg treatment. He was quite terrified by the IV insertion (in the adult ER), ambulance ride, and initial monitoring of his vital signs. Prior to this, he's been quite healthy. After the single IVIg treatment, his platelet count rose to over 100, but then dropped back down and has been in the 30's for several weeks at his weekly blood count check.

Generally, he's a very friendly, outgoing little guy who has always loved "school" and his teachers. However, ever since his hospital stay, he has been incredibly clingy and cries and clings to me as if he's scared every time I drop him off at daycare. When I ask him why he doesn't want to go to school, he either says "I'm too tired for school" or "I don't have time for school." However, when I keep him home, he plays like a normal 3 year old boy (doesn't seem overly tired). I am wondering if anyone else has had a young child who seems to exhibit a form of Post Traumatic Stress Disorder after being treated or while being monitored for ITP? Additionally, does anyone have any recommendations to help settle his fears of being away from Mom and Dad?

Hi there, how is your son doing now?
Mine is three, diagnosed just under a month ago. He has been going to pee ever 20 minutes and has been a little clingier than usual, so yes, I'd say he's experiencing some anxiety.