Can't Go to the Bathroom - Extreme Pain

For 2 weeks I have been having extreme pain when going to the washroom. It started when I became irregular from a medicine I was taking. Today it was so bad that I havent even gone since yesterday morning. The stool is there but i'm afraid to let it out because its hard and very painful. I tried ex lax and that didnt help and I went to the clinic today and the gave me a glycerin lubricant and that still didnt help. What do I do now? It's extreme pain and now im getting cramps. How do I get it out without pain?