No more kids!

I'm so happy I have my son but due to the fact I have lupus and some other complications there is nothing in me that wants to put myself through the whole pregnancy/labor and delivery experience again. I'm getting so frustrated and tired of friends and family who keep asking when I'm going to have another baby. Also I can't stand when people tell me I'll change my mind in a couple years. Is anyone else frustrated with people asking about when they're having more kids?