As most others will most likely reply, 19 days isn't long enough.
Give it a good 3 to 4 weeks if not more.
I've only brewed a handful, so I'm no expert. But remembering my first
batch, after bottling I decided to open bottles at certain intervals to see how
the bottle carbing works. I opened one at 7 days and 14 days and they both had little to no carbonation. At 21 days I was suprised... fairly well carbonated, a big difference! after 4+ weeks I had tasty well carbonated beer.
I think it's a lag thing. It takes a while for the (probably dormant) yeast to start assimilating the new sugars and fermenting. But once they kick in they'll get it done.