good ways to tell parents

I'm almost 8 weeks. I haven't told my parents yet that I'm pregnant. I want to really bad because it's keeping me from being really excited. I'm just super nervous to tell them. I'm 27 so this shouldn't be a big deal. I'm only so nervous because I recently moved back into their home after breaking up with my boyfriend. well back in November we got back together but I still am living in my parents home. we were broken up for 2 months. 
any advice on ways to tell them? I'm expecting them to not be so happy even though I'm 27, had been with my boyfriend (who they like) for 2 years, and we are together now. 
ugh I'm such a wimp! lol how did you girls tell your parents about an unexpected pregnancy?