22 month old autism?

So my 22 month old son started banging his ears when hes watching a learning video he doesnt like or he will cover his ears and/or pull on them. His only word is mama (he spends all his time with me, dad works out of state). He walks, runs, plays like any other child he climbs furniture, laughs, plays with cousins (ages 5, 3, and 16 month old)and if i ask him to do something he will, most of the time. My question for you ladies, have you had a problem like this with your child? Is this normal or is this symptoms of autism? Im just worried, like any other mother. Am i overreacting?