PLEASE HELP ME

Im 17, 212 pounds I've been eating healthier and lost 15 pounds so far. Doctor gave me lexapro for my anxiety, took it for 3 days then stopped because of how horrible I felt, I woke up with chest pain that went away after 15 minutes. But as the day(s) went on I felt like my skin and chest was burning, pain in my left boob. Pain under my left breast. Made a doctor's appointment and they gave me an ekg, said my heart was perfect. I've had 3 ekgs in the last 5 months, everytime they came out good. They took my blood pressure (it was really high, like 190) so they gave me a bp pill and some to take for 7 days. My mouth and nose feels so dry, and when I lay on my left side I feel like I have to work harder to breathe, like I almost stop breathing.

I turned over on my right side and didn't feel this, is this a side effect or withdrawal?? Please help me I am so afraid