Your son's behaviors sound like they are more related to SPD (sensory processing disorder) the chewing on clothes, the temper and even the use of security words or phrases such as "I'm hungry" in times of distress. Go to google and do a search for signs of sensory processing disorder.
Also, the main features of autism are
Lack or very little eye contact
Lack of social skills, not able to read social cues such as facial expressions or tone of voice
Rigid routines
Lack of reciprocity (they don't understand back and forth activities such as playing catch)
Stimming behaviours such as flapping hands, spinning, making vocal sounds etc
Feeding difficulties, they avoid certain textures or they only eat limited foods.
Abnormal sleep patterns
If you are concerned about your child's development, please contact your local Early intervention Regional Center for an evaluation.
Good luck!