reflux?

Last week I had an angel baby. He ate, he slept, then repeat. He was having some gas issues (or at least I blamed gas) and would get unsettled (i.e. loud groaning) from about an hour after a feed, but only sometimes.
He's been a spilly baby from day one, my only comparison though is DS1 who had silent reflux and barely ever spilt, he also barely ever slept before going on gaviscon at 4mths.

Anyhow, so DS2. He's 5 1/2 weeks and he's started crying in his sleep. I mean pained loud crying. Each bout of crying will go on for a few seconds, upto maybe a minute, but it doesn't seem to wake him.

We've put the bassinet on an angle (didn't seem to help) and as of 4am this morning he's sleeping on his side (in one of those sleep positioners). The sleeping on the side seems to help a bit - I think.

I think it's reflux - though I'd like to hear from anyone who's got an alternative diagnosis.
Is it normal for a baby not to have a problem with it for the first few weeks and get upset by it later?

Also, we've got gaviscon still in the cupboard from DS1. It says not to use it on under 1's without the Dr's recommendation. I think I should give it a go anyway. Anyone think is is a good/bad idea?

DS's reflux didn't seem to kick in until somewhere about 4-6 weeks either (foggy memory).
I would be inclined to try the gaviscon, you know your baby, and sounds like you know reflux too. For us though, nothing helped until I eliminated dairy from my diet, take a look at the cryingoverspiltmilk website (if you haven't already)

Yeah our baby's reflux came later... dr prescribed gaviscon and it worked a treat, we only gave her half a dose tho, so maybe thry that for a start, 1/2 sachet for 110ml of milk. i tried avoiding diary too and that seemed to help, altho she seems ok when i have it now so long as i don't have it for days, the odd few days a week is fine.
Doesn't sound like wot she had tho, i think she also had abit of colic for 2 weeks thankfully no longer, nothing would settle her. reflux is typically accomapnied by backarching our dr said and stiff legs, if he doesnt get that then may not be reflux? could be some sort of tummy pains maybe? so hard to know when they can't talk eh.
Good luck.

Thanks all. I tried gaviscon, 1/2 dose but I didn't manage to get much in, so probably more like a 1/4 dose.

Then later that night his temp went up. We went off to the ED, then he was admitted, then 2 days on AB's, now we're home.

About mid-night on the second day in hospital, I realised he'd gone back to "normal". Dr said it would be a virus (code for I don't have a clue) and that it got better on ABs was a coinsidence.

Either way, we're home and DS2 is happy again