Anxiety in pregnancy, what helped you?

Brionna
I had anxiety when I was younger, but it's gotten better the older I got. My oldest son is 8 months old and I had no anxiety during my pregnancy with him. I am now 29 weeks pregnant with baby boy #2 and my anxiety has hit an all time high. As silly as it sounds, I'm constantly worried that something awful is going to happen to me. I'm constantly googling symptoms and even though 4 doctors have told me I am perfectly healthy (I was worried about a blood clot because I've been short of breath) I keep thinking, what if they missed something? I don't want to leave the house because my anxiety worsens and I cry every time my husband leaves for work because I'm so worried that if something IS wrong with me and I pass out etc, my poor son will be all alone. 
   
So, my question is, what helped with your anxiety while pregnant? Any breathing exercises or articles to read? It's becoming debilitating and truly affecting my day to day life. Thank you in advance to anyone who actually read this whole thing and has some advice for me because I truly don't know what to do.