I know this sound stupid but...

[murphy36]

DP does a bottle feed in the night whenever DS 3.5m, wakes. This was BF 8pm, FF 2am-ish, BF 5am + clusters until 8.30ish and a nap.

DS has stopped waking at 5am. Do we need to put in a dream feed or add a FF in the day maybe?

DS had 13% loss @ 3d and has had slow weight gain , born 75%ile and then dropped and tracked 25%ile.

I know lots of people will be 'thank god for the sleep' but I don't want him dropping down again.

what age is he now? How do you feed in the day ie breast or bottle?

3.5months BF in the day. Decided to top him up last thing at night and see what happens

I think at this age they are able to wake up if hungry. I would leave him to sleep, he has to go through the night w/o a feed at some stage, doesn't he? Maybe get his weight checked if worried.

I was in an the same boat. Dd dropped a huge amount after birth and i struggled with bf, i didn't know what i was doing, she wouldn't latch and so we ended up bf and ff. She slept through the night at 7 weeks old for the first time and she only had 7 bf's a day and 3 x 2oz ff. I took her to get weighed regulary for the first 4 months and the centiles did go up and down so you just do what you need to do. Personally i would let him sleep, if he's hungry he'll ask for it. If you're worried about his weight just keep an eye on it.