Mentally Exhausted from being Pregnant

Lately, I just feel lazy, unmotivated and tired. I'm a soon to be single mother. Lonely and sometimes sad. I still have baby stuff to buy, and I am due in 5 weeks. Mentally I feel like a failure because I'm doing this on my own. My ex isn't planning to help out, and is living life. Don't get me wrong, I am excited for this baby, but lately I am so done with everything. I just want to stay home in my bed and not move, just sleep. I still go to.work but even that is a drag. What is happening to me? Why am I like this? I hope it gets better before and after the baby.