You're not being paranoid and being in an environment of negativity can affect your outlook but by the same token it can only "hold you back" if you let it. Life is going to always be full of less than ideal environments for success in pretty much anything. The thing is that you have to not rely on the environment you're in to succeed at what you endeavor to succeed in. Don't let the environment, people around you or other things outside yourself dictate whether you can accomplish something or not. Find ways to do so in spite of the environment. After all is accomplishing things when it's given to you (or easy) really success or is success being able to overcome those things that would seemingly hold us back and succeeding in spite of it?