Depressed

Anyone else feel sad or feel like you don't wanna do anything? I've been feeling sad and crying a lot. This is my fourth pregnancy. I am currently 23 weeks pregnant..I've never felt depression in my other pregnancies, I'm just wondering is this normal? I have had lots of stress lately and it doesn't help that this pregnancy has been so rough on me. I've lost 15 pounds, haven't been able to eat certain foods or do certain things because of my pregnancy nausea!