No Energy

I don't seem to have any energy at all this evening. It is 8.30 pm and I feel like going to bed, except I know that I wouldn't sleep. I know my blood sugar is low but I also don't feel like eating anything. I have been like this the last few nights in the evenings. Feeling low and not being able to sleep. I have been fine in the day, and have been eating normally so I'm not sure what it is.