The Napoleonic Wars didn't start until 1803, dude. Press Ganging was a regular and constant tactic long, long before 1803. Again, you are full of shit. Britain didn't just wake up one day, shit their pants because of Napoleon, and go, "By jove! We had better start enslaving merchant ships or we shall never defeat this French chap!" They had been doing it for a long fucking time, and with regularity. They did it to us the entire time we were a colony, and they did it to us after we declared independence, and by the time 1812 rolled around, we finally had had enough of Britain's shit and threw down the gauntlet over it. By the time we sat down for a treaty, Britain had gotten the message that we were sick of the press gangs, that it was enough of a factor to bring us to war, and stopped doing it. Think it's a coincidence that they never resumed impressment after the Treaty of Ghent? Even though Napoleon escaped shortly after and went to war again?
Also, America HAD successfully captured Canadian land, including what is now Ontario. The return of this territory was central to the Treaty. So no, it's not like we were "driven" out of Canada. Britain captured some American territory, America captured some British territory. We signed a treaty, gave each other each other's land back, and then immediately after the treaty was signed, we had a major victory in New Orleans. So no, at worst, the war of 1812 was a stalemate. But it sure as shit wasn't an American loss.