Measuring behind :/

I had an ultrasound at 36 weeks because my belly was measuring small, and they wanted to check on him. They discovered that his abdomen is weeks behind where it should be, and the rest of him. They’re worried he’s not getting enough nutrients, they’re monitoring him closely via nonstress tests twice a week and another ultrasound at 38 weeks, and then wi decide if he comes out early to continue developing on the outside. I kind of feel like a failure already for not being able to provide him with what he needs... but know I’ve been doing everything I need to do. Has anyone else had this happen? Was the baby okay?