Dear Friends, I want clarification from you!!!?

I already asked questions related to this topics coz i am in confusion. My LMP was on Dec 10th and till now i didnt get my periods. In the month of Feb i checked with urine test twice and i got the result negative. Later i had discussion with my gynae and he suggested me to take progestrone tablets he told that i may be pregnant or may not. I took the tablets for a week as suggested by him and now i am having the symptoms of very severe lower back pain, sore with little pain am i pregnant? i am going to have consultation with him again in a week before that i want to share my feelings with you and get some from you friends plz help.