Sertraline
"I took sertraline from 2011 for GAD, Panic Disorder, Social Anxiety, and depression caused by anxiety, and eventually weaned off in August of 2015. These past 4 months have been miserable, so I just started back up on it 2 days ago. The first time I was on it, it worked great, it just took some time to get used to. I had forgotten just how bad it was for me during the first month though...  I've taken 2 doses now, the first was 75mg but I reacted very poorly to it so I took only 50mg with the advise of my doctor last night. After an hour of taking the second dose, my anxiety skyrocketed. I hardly slept last night at all because of nightmares and waking up in a panic. It is also causing strong nausea. Thankfully, I know it gets better."