Difficult situations are some of the worst and best. Yes, you may feel the need to smoke or cut, but then again, situations like these can be good to help show yourself that you can be strong and to give yourself more credit.
Smoking and cutting is a very dangerous mix. I quit smoking probably... 3 years ago? and I still occasionally get so anxious from not smoking that I get urges to use
sh instead or the other way around. You can't let the addictions overpower your will to get better. Feeling better for the long term should be much more important than short term relief.
Instead of smoking or cutting, you should try some of the alternatives. The best way is to go through the list and find one that makes you feel better, or stops the urges. Or whenever you get the urge to either smoke or
sh, you can do something that you like/love to do (harmless stuff). Maybe go out, write, draw, learn how to play an instrument maybe? A few friends of mine draw on themselves with red markers or lipstick instead, there's also the butterfly project.
Stopping both of these will not only give you healthy ways to deal with stress and such, but you'll feel so much better once you get over the first few weeks.