I quit today!

I started smoking exactly a year ago today, I am a student and am living out of home, I also happen to struggle with anxiety outside of smoking (which is the reason I started and couldn't bring myself to stop for so long). It's been 7 hours since my last cigarette and already I'm feeling irritable and grumpy at literally EVERYTHING. I mean, there was a point where I was smoking a pack a day until just recently, and that was within a year of smoking for the first time ever! I wondered if anyone had any tips on how to not be a crazy lady when quitting?