So tired

Sometimes I wonder how and why in so tired. I get a good amount of sleep and I eat a good amount of food a day, but I find myself struggling through my workouts. I'm not sure if it's because I'm pushing myself or if I'm just extremely exhausted, but it feels like I work 3 X's as hard for this. To me that's very satisfying. I love knowing I'm pushing my body to its limits. 

Today's workout:

Dumbbell rows:

20 lbs 20 reps per arm

Barbell curls:

30 lbs 15 reps

Repeat 5 X's

Hammer curls:

2 X's 15 lb Dumbbells 15 reps per arm

Cable row:

55 lbs 20 reps

Repeat 5 X's

Face pulls:

40 lbs 20 reps

Cable curls:

50 lbs 12 reps

Repeat 5 X's

Cardio:

Elliptical:

20 mins intervals

Treadmill:

10 mins high incline speed 4.5 mi