Possible Trigger Warning!!!

I've been on Lexapro for a week now and have suffered with sickness, shaking, headaches, yawning. The sickness has decreased but I'm concerned because I have days where I feel fine then I get this out of the blue horrible feeling of doom hit me and I feel very depressed and emotional and basically suicidal. My doctor prescribed me Valium to calm me, which has made me feel like a zombie but appears to be working. The thing I'm afraid of though is that when I am no longer on the Valium the horrible thoughts will just come rushing back.

Has anyone else experienced this and if so did it go away?