My son is starting to realize he's different and it breaks my heart 💔

I have a 15 year old on the spectrum. I'm a single mom because I lost my husband when my son was 3. It's pretty much been just us and it gets isolating and lonely and stressful. He has his anxieties and problems due to autism. He gets attached to certain items like his blankie. He wets his bed nightly so he wears pull ups and when he's sick he won't use the toilet at all so he wears them during the day. He had an aide at school and today he said to me "Mama. Why do I have an aide?" I said for extra help and he asked why don't all the kids at his school have aides. I said they don't all need the special help and he asked why does he need it. I tried my best explain he's different. He then asked said to me "Mama. My teacher told me that toddlers wear pull ups." I don't know the context of that conversation so I'm not gonna be mad at the teacher but I said yeah so he asked why does he wear them. I told him because some kids have a harder time holding their pee at night. He said to me "So when you say some does that mean that the other kids at my school don't ?" I said some might and he asked why does he have to and I said because he has trouble holding his pee. So he asked why does he have trouble and eventually he wasn't getting I assume the answers he's looking for so he got mad and said I hate you and cried to his room. He was hitting me with questions I didn't expect and it breaks my heart that he's realizing he's different. I don't want him to feel hurt and i feel like I'm failing him as a mom.