Welcome to our community!
The sad and cranky is part of the withdrawal process and your body learning to live without it. That part of your quit WILL end - get through it the best you can. Warn loved ones and co-workers and apologize ahead of time for any discomfort you might cause them. It IS temporary - and quitting smoking is the BEST thing you can do for yourself and for those who love you. It does get easier as you get time under our belt - if it didn't - not many would make it out alive!!! 
The important thing you can do right now is to educate yourself on what nicotine does to your body and mind. To that end, I highly recommend Allen Carr's “The Easy Way to Stop Smoking.” This is an easy and entertaining read. You can search for it online or at your local library. If you do nothing else to get ready for your quit, please do give this a read.
You should also read the posts here and perhaps go to the pages of folks who you think might be helpful. You might visit whyquit.com, quitsmoking.com and livewell.com for the good information contained there. @https://excommunity.becomeanex.org/groups/best-of-ex has lots of blogs written by members of this site with their experiences and guidance. Here is a video to inform you further about nicotine addiction: https://www.youtube.com/watch?v=IpWMgPHn0Lo&feature=youtu.be.
It will be informative if you do the tracking and separation exercises recommended here on the site. As you track each cigarette smoked, note its importance, and what you might do instead. Put each one off just a little to prove that you don't NEED a cigarette just because you think you do.
The idea is to change up your routines so the smoking associations are reduced. Drink your coffee with your OTHER hand in a place different from when you smoked. Maybe switch to tea for a bit. If you always had that first smoke with your coffee, try putting your tennies on right out of bed, going for a quick walk, then taking your shower and THEN your coffee! Rearrange the furniture in the areas you used to smoke so the view is different. Buy your gas at a different station. Take a different route to work. Take a quick walk at break time where the smokers AREN'T.
You need to distract yourself through any craves. You can take a bite out of a lemon (yup - rind and all), put your head in the freezer and take a deep breath of cold air, do a few jumping jacks, go for a brisk walk or march in place, play a computer game. Keep a cold bottle of water with you from which to sip. Don't let that smoking thought rattle around in your brain unchallenged. Sometimes you need to quit a minute or an hour at a time. You will need to be disciplined in the early days to distract yourself when a crave hits. Get busy! Here is a link to a list of things to do instead of smoke if you need some fresh ideas:
https://excommunity.becomeanex.org/blogs/Youngatheart.7.4.12-blog/2013/02/25/100-things-to-do-instea...
The conversation in your head in response to the "I want a cigarette" thought needs to be, "Well, since I have decided not to do that anymore, what shall I do instead for the three minutes this crave will last?" Then DO it. You will need to put some effort into this in the early days, but it gets easier and easier to do.
Stay close to us here and ask questions when you have them and for support when you need it. We will be with you every step of the way!
Nancy
