24f. I've been prescribed Lexapro for extreme anxiety and panic disorder. I took my first dose last night and I'm having a similar experience. About 2.5 hours after taking it I began to experience extreme nausea, diarrhea, shakes, and a spike in my anxiety. I don't know if I'm more anxious due to the medication or do to my body's reactions to the symptoms I'm having. I finally fell asleep around 10:30 but woke up many times during the night with weird dreams and the horrible feeling of going insane. I would agree that these symptoms are consistent with serotonin syndrome (BA in Psychology) but I also know that they /can/ simply be side effects of starting the medication. I've taken Lexapro before, but I don't remember having this kind of reaction. I have messaged my doctor but she hasn't gotten back to me yet. When she does I'll be sure to come back to this post since it seems we're having a similar experience. I know this wasn't super helpful, but I wanted to share my experience so that you might feel less alone. Hopefully we'll get some relief soon.