Congrats, OP, on Day 3! That's a *VERY* big step! The first few days are the hardest, and it gets easier as the days go by. The longer you can hold off your cravings, the better your chances of staying smoke free.
I quit cold turkey 16 years ago (and have not touched a smoke since). It look me about a dozen tries before I finally kicked the habit. And, now, I can't stand the smell of smoke and don't have any cravings for nicotine at all.
What I found helped was keeping small goals, taking it day by day (as others have mentioned). Initially, my goal was to not smoke for a day, then my next goal was to not smoke for 3 days, then a week, then 3 weeks, and so on.
My advice is this: be mindful of your cognitions. Your mind will come up with any excuse for you to light up and smoke (eg, you might be thinking "oh, just one cigarette won't hurt" or "I'll just put this unlit cigarette in my mouth...that won't hurt", etc). The next thing you know, you're back to smoking again. Bottom line: don't trust anything your mind tells you.
Good luck!