Yesterday I tried Drill Max for the first time and I did the cardio blast premix. While I was doing one of the segments I heard something pop in my back, but I felt no pain so I continued with the workout until the end, then I trained my legs and then when I tried ab work I just couldn't handle the pain in my lower back, especially the coccyx (aka tailbone). I had to stop immediately, do some stretching, take a shower, and go to bed. Today the pain was bad because I'm sitting pretty much all day, but it was worse if I tried to pick up something from the floor, or if I tried to do something that required bending my back. I'm stubborn so I still tried to exercise. I had kick max (segments 1 and 2) scheduled for today with some upper body weight work. I could finish segment 1 with modifications, but when it came time for the blasts I just couldn't do them. I had to stop (I didn't even do the upper body workout), stretch and here I am posting and not knowing if I'm going to be able to exercise tomorrow. It's a bummer that this is happening now when lot of doctors (including mine) are away for the Holidays until Jan 2nd. What to do what to do... I don't even know if this is serious enough for an emergency room visit which is my only option at this time. Weird. What do you think I should do? Thanks in advance for any replies.