Is gst required for commission agent?

I am a student doing part time business promoting services of a particular company say A i make 80-90k in commision a year but i usually spend 30-40k a year on advertisment as well.so my net income is something around 50-60k.The company A usually use to cut TDS only which i file IT return and get the amount back but now they are even cutting GST 18% with it (as i have not given them the gst nos.) & the Adv company is also cutting 18% on the amount that is spend on adv (before it was less ~12-14% service tax which i didn't care ).So my income has come down to peanuts.What should i do? I have a saving account only .Do i need to get a propertiship license & a current account to get a gst ? I am totally confused..I have read that any income below 2.5 Lac is free from tax & here i am paying 18%+18% on both side that i am not able to claim . Any help would be helpfull? Thank you.