Night diapers - daily leaks in size 3 Huggies overnights. What can we do?

FirstTimeMom💁🏻🤰🏻🤱🏻

My baby is 5 mo and about 17 lbs. we bought a value pack of size 3 Huggies overnights and are barely halfway and he’s leaking thru them every night. I feel like a laundry maid cleaning poop and pee so much out of his clothes and sheets.

Do you use night diapers ? Any suggestions ? I read somewhere to size up 2 sizes if you’re leaking is that right ?

Last night he leaked thru his diaper, outfit Merlin suit crib sheet and the leak proof sheet in his mattress 😩

What are we doing so wrong- am I putting it on wrong he’s in the weight limit for it (16-28lbs!!)

Ftm mom here and so so confused ☹️