The closer i get to having my son, the more sad i get....ADVICE?

Don't get me wrong, I am COMPLETELY ready to have my son. I haven't seen him and im already in love but 5 months ago my 2 1/2 year old died in a car accident with my boyfriends father. Well im currently 25 weeks pregnant and it seems like the closer I get to having my son; i get this sad feeling. Especially since we are more than likely going to have to use my sons old room for the new babys' room. This feeling was there for a while but didn't fully hit me until about a week ago when me and my boyfriend was talking about baby names and he said Travon (a combine of my name Evonne and His travis). I just got to thinking and I remembered my son Trevor and the asshole that raped me about a year ago Traviion. I have been doing a good job for the past few months of not caring and pretending like every things good but now every things coming to a head. An i can't help but feel incediably sad, Is this normal? Advice please.