I got the same problem... it's gotta be the heat because in the winter I'm in top shape & can't wait to lift. Summer time, my diet goes to sh*t from the BBQ's, drinking and being sapped from the heat. I still get there though even if it's a half @ssed workout it's still better than no work out, I just go lighter w/ more reps. Xenadrine does wonders for motivation though!