FTM getting scared

Hey ladies my son is 6 months not yet sitting up on his own. Rolls over but all the way. I noticed since 4 months he is very tense like his upper body. He does bend his arms down but like 80% of the time he is with his arms position by his chest. He is also very hyper like moving his legs non stop arms flapping back and fourth. Like he is sleeping excited 24/7. When he is eating he flaps one or both of his arm up& down the whole time he eats, unless im holding one.. Again im a new mom reading crazy stuff about autism and it’s terrifying me because some stuff sounds like he does. Like moving his little hands a lot.. super hyper, fascinated by ceiling fan lights. Is this normal? Does your baby do this? Maybe im just paranoid.pic of how he tenses up & arms up