Baby not sleeping

I’m exhausted. My husband is exhausted. Our LO will be 7 weeks on Monday. He had a week of sleeping amazingly and now for the past week he has been having a difficult time sleeping at night. I know there was a growth spurt but feel like it’s more than that.

I will put him to sleep then 30-45 min later he’s up grunting and fussing. It’s like he cant get comfortable. He’s been fed, changed, etc. We give him gas drops before bed as well. He sleeps in a bassinet next to us.

He hates being swaddled but I feel that he is waking up due to the startle reflex. Anyone have any insight?