Excited to be pregnant but scared too

LaShawn
I literally just took a pregnancy test. I've been an irritable crazy lady. I'm pregnant which is and should be so exciting but I'm terrified. 
I have a 4 year old, right after he was born I got a Mirena. I took it out at the beginning of May and got pregnant immediately. I miscarried a week after finding out I was pregnant. 
Now here we are 4 months later and im pregnant. All I can think about is what to do to keep this pregnancy. I don't even want to get excited. Happy and sad. Has anyone ever experienced this?