Nursing Makes Me Tired?

So I was talking with my therapist yesterday about how I've been feeling so tired and low energy lately. I keep thinking this is a result of my anxiety. When I was pregnant I felt tired and low energy a lot of the time and it had to do with my incubating a small human. But now I wonder if there's something wrong with me and why I feel almost the same as when I was pregnant tired. My brain feels asleep at times and, even when I get lots of sleep, I just feel like I want to lay on the couch and watch a good movie.

I keep thinking, man, I need to get over this. What is causing this? And she said something that was so friggin' obvious I can't believe it! Nursing can make you tired. Oh. Right. Duh. I'm feeding another person who's getting bigger and I can't ever seem to get enough food. Which could be part of the problem. Maybe I'm not eating enough. On the other hand, I eat SO MUCH I have been trying not to eat so much because it seems obscene. So... I guess that I need to work on that. But it was such an amazing revelation. She said some women need to take naps every day when they are nursing. And I work all day and come home and take care of my baby and I'm still nursing and pumping a lot (and trying to donate extra milk as well) and I'm TIRED! And it makes sense. So now I feel like I can finally give myself a break. What a relief!