I think the only reason he didn’t just tell Regina and Emma when he got to the Snowing’s apt is because he’s conflicted. He’s not going to blurt out what happened to everyone and their mother and place them in danger – he went to Snowing’s apt, not realizing Emma was there, to do the exact same thing he did in NL – tell Snowing and seek their advice.
And really, look at it from his perspective – he knows he’s in love with Emma. Everyone else knows he’s in love with Emma. But as it’s been clearly pointed out, we don’t know what Emma’s feelings are for Hook…general consensus appears to be it’s anywhere from she doesn’t like him/isn’t interested in him romantically to in love with him as well. So…Hook’s supposed to go to her, 1) declare his love to her – out loud, with the words (again, we all know how he feels but he hasn’t actually dropped the love bomb on the girl), 2) not only tell Emma but whomever she’s with and everyone else, and then 3) see if it’s even really that much of a biggie because hey, if Emma ain’t planning on kissing Hook anytime soon, who gives a hooey about Hook being unable to kiss her? Maybe it’s me, but I’d want to knock the idea off a buddy or two before I tell the admittedly closed off, emotionally tattered girl who just learned how to use her magic in the first place too.