First off, I'm curious if these negative people you are talking about are smokers. I know that when I was a smoker, I often got defensive when one of my smoking friends attempted to quit. I didn't try to sabotage their quit but I definitely felt threatened. Looking back, I realize that I was envious of people who were trying to quit and might possibly be successful. If these people who are negative to you are smokers, fight past their negativity and realize that they might just feel threatened by you quitting smoking.
If they aren't smokers and are just jerks, then try to use their negativity to prove them wrong. Don't let them bring you down. I know that is easier said than done but realize that smoking will not make anything better.
The trap I always fell into when trying to quit smoking was feeling that smoking somehow calmed me or helped me cope. The reality is, the only thing it did was feed an addiction to nicotine. Introducing nicotine into your body actually makes you more stressed and doesn't make anything better.
Nicotine really does nothing at all positive for you. It is all negative.
Dealing with a--holes is tough but smoking will not make it any better. It is best to fight through these type of situations. Every time you fight through them, your quit gets stronger.