If it's a virus, you'd feel muscle weakness and all the other things that go along with a virus, unless it's one of those 24 hour stomach
bugs. If it is, it'll go away. Digestive problems are one of the most common side effects of medication. From what I understand, the proper way to go on Lexapro is in 5mg intervals to slowly get your body used to it. Do you have a psychiatrist expert in these meds, or just a regular doc? And what's your instinct?