Has anyone else been proscribed promethazine for sickness?

I was given it on Monday from the doctor cause I've had really bad nausea for weeks and sickness. I was at the point where I couldn't do anything cause I was so ill :( I haven't felt as bad since taking promethazine but I feel very strange whilst taking the tablets as I feel really drowsy and my mouth is so dry. I've read on the Nhs site that you shouldn't have them for more than 7 days but my doctor didn't say anything about this?? Also is it safe for baby he said it was but from reading things online I'm not sure about it :/ I'm 8 weeks pregnant btw