Bumperlicious
there are things you can do , to keep yourself positive, but if you sare genuinely depressed, then medical help is needed..as you know!
my own experiences with PND , the first time, were severe, with 4 years of illness, various ADs, therapy , etc culminating in a hospital stay of 3 weeks.. a lot of it was to do with DS;'s birth..so when i was well, and pregnant with DD, i spent the entire pregnancy focusing on getting a positive delivery and birth this time...and i had moments of complete anxiety and upset......but it was time well spent.. i achieved a vaginal delivery, no intervention, which was what i had aimed for...baby blues day 4, then nothing..she is 17 months now and not a hint of PND at all....and this was after being told it would be virtually inevitable...
get your safety nets in place, so that should you need them, they are there....focus on positive thinking, don;t listen to the negative..i used to ask people who were being negative around me, about the birth especially, to please be more positive...i did visualisation every day and lots of research about birth..which took my mind off things....
there is a lot of support here too...so use it !
if you do feel low now, lower than you think you should and you are concerned, don;t wait for the 20 week appointment...see your doctor now
HTH!