The dream is over

The thing we've been dreading for months has finally happened.
Ari has started waking in the night.
Believe me, that in itself isn't the tough part. I've never minded getting up in the night too much.
It's trying to figure out why that's the killer.
Ari has been sleeping through the night fairly consistently from about 2 months of age, which is amazing. We know how lucky we've been.
And in the last 2 months, we've been exceptionally lucky. We've put him to bed at 7pm, he usually went down without a peep, and stayed there until around 6.30-7am. Bliss.
The past 2 nights, though, he's woken at around 2am, I've given him a feed and he's gone back to bed until 7.30am. Why?
Is he hungry? Is he too cold? Too hot? Wanting to socialise and chat at 2am? Can't put himself back to sleep?
I've tried to think of any factor that might be affecting his sleep - are my breasts not giving up as much milk? I've been feeling under the weather for the past 3 days - is that contributing? Is it because I've just started Ari on new foods like toast, porridge, etc?
Of course, in these instances, there's no easy answer. The book Baby Love says any night waking after a baby is 6 months old is NOT to do with being hungry.
Try telling that to a baby at 2am, and parents who just want to get back to sleep!
But therein lies the trap. Do you feed the baby and set a bad precedent you have to follow every night? Do you let the baby cry - and possibly deprive them of food when they are actually hungry?
It's really hard.
Lots of stuff is happening to Ari at the moment. He's wanting to hang out with us more. He's becoming a nightmare to breastfeed because he's more interested in what's going on around him (even my t-shirt, or his own hands are far more interesting than feeding).
He's getting out more, eating different foods, doing more new things.
Maybe it's just a phase he's going through. Fingers crossed!