Loosing weight again

Through out this pregnancy I have smoked and felt so guilty for it. I’ve tried to quit a few times and each time my weight drops and my mood becomes so unstable. Since I’m closing in on labor I have been smoking less and less hoping to quit but that’s not happening so I am just hoping the small amount of thc in my system won’t cause any problems with the doctor. It just upsets me that when I try doing something good for baby like quitting it causes worse things to happen. I’m almost 39 weeks and instead of gaining a pound a week I’ve lost five pounds in a week. Doctor isn’t concerned but it’s best if I keep smoking so I can eat. I really can’t wait for marijuana to be more acceptable by everyone.