Not doing well

I'm really sad tonight.  I spent some time with my cousins and their kids, one has three, the other has two.  And I don't get along with one of the cousins and her husband pretty much most of the time.  I found out that my parents are hosting them at their house for the week so they can visit with my other cousin while they're in town.  Kind of confusing, but the main point is my parents know how I've been hurt by things my cousin's husband has said to me and I feel like they're betraying me by letting them stay over and also my father is giving work to them as well (the husband got laid off from his previous job).  I told my Mom I'm not going to the Christmas eve party or to their house on Christmas day.  Then I did something bold and told her to never call me again.  What is wrong with me?  I got so jealous when she was telling me that my cousin's kids were over and climbing all overt things and laughing.  I just felt like she likes them better and I feel so hurt.  I am so sad we don't have kids yet.  And I can't stand my cousin being at my parents house with her children.  Usually when I'm hurt I just pull away, and I guess this instance is no different.  This evening while with my cousins and their children, all I did was knit.  I talked a little, but was mostly trying to focus on my knitting so I wouldn't feel sad.  My Mom has no idea how hard it is to not have kids.  She told me once she cried each cycle after she was married until she found out she was pregnant with my older sister.  A whole three months after she was married.  She can't possibly know how I feel.  I wish I didn't even know they were staying over there.