What am i doing?

I am frustrated. I had to go to 2 babyshowers this weekend, have another friend that just had a baby and my boyfriends sons both recently had babies.  I cannot understand how I cannot have children.  I would be a great mom.  but the lord has a different plan for me I guess. I just long for a normal family life.  Something I have never had and not sure I ever will. What is my purpose!!!!