It is so hard not to panic, when you aren't given the proper informaion when we are told something new about our bodies.
As far as I know. It is perfectly normal for a vagina wall to drop during pregnancy or during labour. Well it was with my case anyhow.
Mine is the same, but it has been like this since giving birth to my DD 1 year ago, just hasn't had a chance to recover yet
I went to a GP after she was born as I too though things felt different down there, and she was very helpful. She grapped a mirror and said show me what your concerned about. So I pointed to exactly what your describing, a big lumpy thing hanging right down. She reassured me that it was nothing to worry about, that my vagina wall had collapes a little, but should return to normal after some time. She said that, it happens in some women and not others, some takes longer to recover etc. She also said that it is caused by the pressure, some don't collapse until labour but some do before hand, from the weight of baby.
I hope this helps you a little. I know everycase is different, so if it is bothering you and you want reassurance I would see someone to ease your mind, just incase it is something else, but I'm sure you'll be fine, just another great experience of becoming a mother
Good luck with everything, can't wait to see your birth announcement.