I spent 5 years doing volunteer work off and on with drug addicts.
However - even if I hadn't done that, I wouldn't feel guilty because I'm selling porn, anymore than if I was selling a Mercedez or a vacuum cleaner. Key lesson to learn - IMHO - is that it's not wrong for you to be happy, just because there are others who are less fortunate. At whatever point you decide to do something actively to help, you'll always be more of an asset if you are a happy, satisfied person.
There are two paths you can take if it really bothers you:
a. Something full time that helps the world situation
b. Volunteer work.
And (b) is always acceptable.
