Im just on week three with sust 250 and i feel very tired through out the whole day too. Even on the 2 weeks im on E/C I know im tired but i cant close my eyes cause of the caffeine. I'm thinking that the tiredness will go away once the test really kicks in around week 5, hoping so cause its hard to do dumb bell work when my glutes hurt so much from the sust.. same with cardio
But I do think it is common for some people to be tired on cycle more than normal.