Sounds like you need more calories, and make sure you are getting enough rest.
Is this a new schedule for you? In my experience, increasing the volume of your sched initially can wear you out, but once you get in a rhythm you tend to have more energy throughout the day.
I've been doing this for about a month, so yeah probably. I can try to get enough rest, but the diet thing is difficult... If you ever went to grad school you would remember how poor we grad students are. And there's never enough time. Sometimes all I get to eat in a day are a few sandwiches and some milk.
I do need to fix this though, cause I don't want to crash and burn and impair my long term training.