zero energy and feeling guilty

I have zero energy at 35w4d! I've gained 50lbs and I know that's part of it. I'm not sleeping well. I'm also craving crushed ice and a lot of people have told me that's a sign I could be low on iron. I am carrying a big baby measuring 2 weeks ahead plus having high amnitoic fluid levels. I just want to have energy on the weekends to spend time with my husband and instead I'm napping! Anyone else going though this? Feeling guilty!!!