UGathlete, how long is your workout? I was working out too long in the past...sometimes 90 minutes of lifting with lots of different exercises...and I was feeling like shit afterwards.
Now I choose 3 lifts (for instance in a few minutes I am going to go do SQUATS, DIPS, FLOOR PRESS) and beat the fuck out of myself with 1 work set for each lift with ample warm up sets progressively working to my work set. My workout takes 45 minutes about now.
I also take in a LOT of carbohydrates before, during, and after. Within a one hour window of my 45 minute workout I will consume 100 grams of carbohydrates (a lot for me considering my height/weight).
Doing both of these consistently now I leave the gym feeling better moodwise and physically.