3 days in a roll

Going down for my 3rd training session in 3 days, due to the youth day holiday on mon and a parents-teacher meet on friday, a originally planned mon wed fri training week became tue wed thur training week. What's worse is that ws cannot make it on thur, so i had to take 1 more session this week so he'll take 2 session next week. Originally I didn't really bother too much, I'm just the coach not really having much physical strain on the body right? But my back tells me otherwise. After the tue training my back was already hurting abit, perhaps because I stood for a prolong period of time. Yesterday was feeling the same pain, but add that to playing pool with sz at nght, my back was killing me. After todays training I'll see how it goes. Tommorrow I'm going to start work at G2000, which also involves standing a lot. Ok... bad idea.