Affiliate Marketing Secrets

In 2012 I made $18,000 in self employment income. I am young and have only had 1 real job outside of my home. I was laid off from my last job and needed income fast so I got into affiliate marketing and started making money fast. Soon, I was making more than I thought I would. Recently, I found out that I am suppose to pay taxes on self employment income but I don’t know where to start.
Please help! How much will I owe in self employment tax, federal, state, and penalties all together?
Will I get in big trouble?
How do I go about paying my taxes. I am a little confused so I need as many details as possible.
Thanks!

i gave the entrance exam for amity law school through IPU-CET. i wish to pursue law..i was recently told by a friend that if i do my BA(LLB) integrated course from any college affiliated with IP university then after my BA(LLB) course i will not be able to pursue LLM from delhi university…is it true ?? plz giv concrete information…this is critical for my future.. and also….plz provide me with info regarding the best DU colleges if i change my plans n go for political science hons instead n after that i do my llb n llm frm DU….which one would b more beneficial ?