When I first started on 10mg Lexapro, I had awful side effects--nausea, insomnia, heightened anxiety, zero appetite, every side effect in the book. When I increased the dose, however, I didn't have any of these! I was a little sleepy and jittery but it was so manageable compared to when I first started. If your doctor wants you to increase your dose, trust him. I was skeptical just like you.