8 weeks old baby keep waking up from sleep

Hi,

So my 8 weeks old baby will only wake up for 1.5hr before he's due for his naps. During the day sometimes he will only sleep for 20 mins which is annoying cause i would like him to have longer naps but that's fine. He is sleeping well at night but the process of him going into his deep sleep is so painful. He will cry and fuss at 6.45 pm and asleep as soon as i put him down. Usually by rocking and feeding him to sleep. Every 5,10,20,30 mins he will wake up and cry then i have to go back in the room to put him back to sleep until 9ish where that's time he's usually asleep for the rest of the night until morning with 2-3 wakings for feed. I don't know what's going on with his wakings and how to change that. Any tips i will greatly appreciated. Thanks!