Wakeful 5 month old...

[BelleBoyd]

My DS is five months old and has reflux. He has ranitidine and domperidone which manages it well. He is 16lb and is a big strong baby. He has some solids as his milk intake was quite large-30oz plus.
The longest stretch of sleep he's done is 5 hours but that was a couple of months ago for a short period.
He typically sleeps from 8/9 pm to 11/midnight and up for a big feed and then wakes around 2am for an hour and then 4/5am for 2/3 hours and has a nap around 7/8 for half hour.
He doesn't nap in the day for longer than 30/45 mins. He has 2/3 of these naps.
Basically I've introduced sleep props as I was/am so exhausted. He falls asleep usually with his bottle or being rocked in his pram.
I have a hugely active 4 year old too so it's quite hard concentrating on either one IYSWIM.
My first DD was an awful sleeper and would wake literally every 20 mins so at 7 months used CC and it did work after 3/4 nights.
I'm not sure whether I need to do that again or someone can advise something else I can do in the meantime.
I don't have much time to settle DS in the day whilst looking after DD and at night I don't want to wake her-she's still not a good sleeper.
I'm a single mum and the lack of sleep is starting to effect my health.