Sharing the News!

Erin
Well ... I just found out I am pregnant *yay!* and am absolutely horrible at keeping secrets. My boss told me he just knew I was pregnant and I caved because I can't lie either! And I am happy so why not share. It has been a long time coming. 
I was feeling guilty that my boss knew and my mom didn't. So I went out and bought my son, four years old, a cute big brother shirt and decided to share the good news with my mom and dad. First go around with my now four year old son didn't go well - I got pregnant the year I was to get married. Oops!  My mom didn't talk to me the entire time I was pregnant - missed my baby shower, wedding shower and left my wedding at 8 PM.  I tried hard to forgive her  years later even though what happened didn't warrent the behavior. And she never apologized.
So I went to pick my son up at their house this afternoon and wanted to share the news! I had them read his shirt that said "Worlds Greatest Big Brother" and they quickly changed the subject. Didn't say congrats, didn't ask when I was due, NOTHING.
I am disappointed. Sad. And dumbfounded.  
Any suggestions on how to approach this? I want to be closer with my mom but she pumps the brakes. It has always been this way - the non hugger, no "I love you's" .... I am married, have an amazing son, own a home, have a wonderful job and just don't  get the angst. I feel like it is my last pregnancy all over again and I can't do it. It was exhausting and caused so many unneeded tears. I don't want this again. I just don't know how to combat this or do I even bother.