I don't know how I'm still functioning

34 weeks and working full time. I'm lucky if I'm getting between 2-4 hours of sleep every night. I feel beyond sleep deprived, to the point where i just want to cry. I can't help my husband with anything around the house because I literally get home from work and go to sleep. I feel like a zombie every day, and I wake up feeling like I have the worst hangover ever. Anyone else???